The Coen brothers have a wealth of screenplays that they have written (or part written) that they have yet to turn into movies. We can look forward to a future which will include some, or all, of the below.
THE YIDDISH POLICEMAN'S UNION
On Feb 8th 2009 the Guardian (UK broadsheet) had an interview with No Country For Old Men producer Scott Rudin where he mentioned that "He has already started working on the next Coen brothers film, an adaptation of The Yiddish Policemen's Union by Michael Chabon." Nate, over at Chabon website, sugarbombs.com, has had it personally confirmed by Chabon himself so it must be legit information. Apparently it will be their first writing gig once the WGA strike ends.
TRUE GRIT

5th March 2008- The world's most awful newspaper, the UK's Daily Mail, is reporting that the Coens are set to work on True Grit. Apparently they are to adapt the original Charles Portis novel as opposed to remaking the John Wayne movie. "The book recounts the girl's story," Joel apparently told said newspaper. "In the John Wayne film, she was played older. We want her to be her real age - it's her story!"

This stinks of either crappy journalism or a Coen joke to me. Let's not forget that the Coens have spoken about making a violent western in the recent past (see below).

WESTERN PROJECT
Buzzing about the internet in December was the fact that Joel and Ethan had mentioned that they had written a western movie. Being the Coens it's gonna be kinda violent, Joel; ”We've written a western with a lot of violence in it. There's scalping and hanging ... it's good. Indians torturing people with ants, cutting their eyelids off.” Ethan; "It's a proper western, a real western, set in the 1870s. It's got a scene that no one will ever forget because of one particular chicken."
SUBURBICON

A murder mystery the Coens started writing shortly after Ethan moved to New York. This one still may be a going concern in some sense, as George Clooney has mentioned that it was going to be his first film with the Coens until they decided to offer him 'O Brother Where Art Thou. "It was a small part and I was going to get beaten to death with a shovel. I liked it. It was a great part". Thanks to Ciaran Cassidy for supplying the above info.

More developments in November 2005 with the news that George Clooney is going to direct this, which is great news considering the excellent job he did on his directorial debut, Confessions of a Dangerous Mind, along with the high praise preceeding his follow up, Goodnight and Good Luck. This from Clooney: “I’m going to do a comedy with Joel and Ethan in around a year. I really like working with them and I like doing comedy with them. They offered me a part in Suburbicon a long time ago, and since then decided they have other projects they want to work on, so I called them up and said 'How about me taking a spin at it?' Because it's a really interesting, really funny, very dark comedy." (empireonline.co.uk 23rd November 2005).

Clooney in March 2008 - "No, no, I wanted to do that, [but] I haven't stolen that one away from them yet. I think they are going to do it, I think they are going to direct it, but I love that project. I have a part in it that I would love to play." So it looks like the Coens may direct this one themselves.

ED HARRIS PROJECT
The brothers have thus far refused to elaborate any further on this one. Its a script they wrote with Ed Harris in mind. Mr Harris has has a lengthy and varied acting career, including roles in Glengarry Glen Ross (David Mamet, 1992), Nixon (Oliver Stone, 1995), The Truman Show (Peter Weir, 1998) and A Beautiful Mind (Ron Howard, 2001). None of this sheds any light on what the Coens might have written for him. Sorry. Thanks to Ciaran Cassidy for supplying the info.
OLD FINK
First mention I ever heard of this was in the July 2004 issue of Empire magazine. It is supposedly a sequel in which Barton Fink is now a professor at Berkeley University in the swinging 60's. The brothers apparently commented, "Sure we'll do it, if we live long enough. We don't want to do it till John's really old." Of course they could be just messing about...
GUESS WHO'S COMING TO DINNER
Mentioned in the same article as Old Fink (above). A remake (Heaven's to Betsy NO!) of the 1967 satire, in which a white girl takes her black boyfriend home. The Coens: "What you'd have to do was an exercise in pure style. That's another dream project gone." On one occassion, the subject came up at the end of a string of clearly untenable projects, after Joel reiterated his desire to make a dog move 'Like "Old Yeller"', he elaborated. Ethan's response to this was 'We keep arguing, Joel wants to do a dog movie and I wantto do a farm comedy like 'Ma And Pa Kettle'... y'know we'd cast David Straithairn and Kathy Bates.' It has to be said the Coens are so wilfully perverse that you couldn't rule any of those out entirely. But they won't happen. Probably.
CUBA LIBRE
This one was talked about a loooonnng time ago and the Coens have confirmed (again in the Empire article mentioned above) that they never intended to direct this adaptation of Elmore Leonard's novel. "That was never a project of ours to direct, it was just a writing job."
TARZAN MOVIE
This was rumoured back in May 2001 over at Ain't It Cool but has resurfaced lately (May 2004). The 2001 rumour started because of a comment Billy Bob Thornton made during the press for The Man Who Wasn't There. I suspect he was joking but you never know! The recent rumblings have begun because of an "article" in the British tabloid newspaper, The Daily Star, (reported on t'internet over at Dark Horizons) which claims that the Coens are set to write and direct the movie with Hugh Jackman slipping into the lord of the apes' well-worn loin cloth. The fact that this originates in such an illustrious bastion of truth as The Daily Star removes at least 90% of the credibility from this story. More as it happens.
JESUS QUINTANA "spinoff"
A rumour about a movie dealing with Jesus Quintana's back story started because of a comment John Turtutto made in an interview. To quote the man himself- " We actually may do a continuation. We're thinking of doing a down and dirty movie with him-- Jesus: The Second Coming. That thing is huge all over the world. People go insane over it, so we thought we've got to come up with the right story. We're in discussions to do it." Personally I think this is a joke on Turturro's part. I would be very surprised if this movie was made... though it would be cool!

Latest is a comment made by the Coens in the July 2004 issue of Empire magazine: "John [Turturro] wants to do it. We could call it The Passion of the Jesus, so now would be a good time. Good title, too." I would kill to see this movie made.

September 2007 - John Turturro has been talking about a possible Big Lebowski Jesus Quintana spin off movie again. In an interview with Gothamist.com he brought it up, pertinent parts below but you can read the whole thing here.

Back on the subject of cult classics, The Big Lebowski has gone on to become one. Yeah, look at that. Didn’t do great here originally but now it has.

Were you surprised by the lukewarm response the film received when it came out? No, wasn’t surprised; I didn’t realize how funny it was.

When I first saw it in the theater I thought, “That was interesting.” But then over repeated viewings it’s just gotten better and better for me. One of my favorite films. It’s really, really, really – It’s really, really good. It’s really, really good! It’s hilarious. Maybe someday we’ll do a little spin-off of it. We’ve talked about it. But we’ll see.

Is there any chance of that? I want to make a Jesus film but Joel and Ethan… We’ve got to sit down. Maybe next year I’ll get them to write it. We’ll see.

Was that your idea to lick the bowling ball? A lot of those ideas were mine, yeah. But Joel and Ethan and I kind of share the same sensibility. And that’s why they were so helpful on my film, editing it. Because I don’t have to explain things to them. They understand. And they know how to make it better.

Thanks to John for emailing this in.

In September 2008 many of the stars of The Big Lebowski were quoted on the internet on the subject of a Leboski sequel - Steve Buscemi, whose character Donnie died at the end of the original movie, reckons a Donnie-centric prequel would be the way to go: “You could have the prequel to ‘The Big Lebowski. It could be the life of Donnie the surfer because remember, he not only bowls, he surfs.”

Julianne Moore had this to say: “I think she has a role in everybody’s universe, Maude abides too! She’s with The Dude somewhere, man, she had The Dude’s baby, remember? So there’s a mini-Dude out there. [Maybe the movie] is called ‘Mini-Dude’!” About Turturro’s dream Jesus spin-off she said: “He should! What a great character. He’s incredibly powerful.”

Philip Seymour Hoffman, the Big Lebowski’s sycophantic assistant, Brandt, has said: ““That’s just like a sick thought, isn’t it? I love that [Lebowski] has a life now. I had a ball making it.”

HAIL CAESAR

I don't know much about this one at all other than it is to be a "Roman farce" hopefully starring George Clooney.

JULY 2005- George Clooney is to star and couldn't resist spilling the beans. He is to play the leader of a 1920's theatre troup who are putting on a production of "Julius Caesar". Clooney is quoted as saying, "The star would have an idiot toga and a pencil mustache." and describes his character as "an absolute jackass." Clooney also described this movie as the third part of his "idiot trilogy" after O Brother, Where Art Thou? and Intolerable Cruelty.

From Empire magazine's January 2008 issue as part of a 13 page Coen brothers feature; "The story of a 1920's theatrical troupe's vain attempts to put on a production of Shakespeare's Julius Caesar seems to have been relegated to the backburner. At various times it's been set to star George Clooney and Tim Blake Nelson."

TO THE WHITE SEA

An adaptation of the fantastic novel of the same name by James Dickey (Deliverance), about a WWII gunner who ends up behind enemy lines in Japan. Largely a survival tale. This movie was seemingly all good to go. A script was written and it was partly cast. Brad Pitt was to star and a reported budget of $60m was bandied about. However, Pitt opted out and something went wrong with the budget. The Coens could no longer raise the required cash and the movie was shelved indefinitely. A huge shame because the movie was to be largely dialogue free which would have been very interesting. Latest is a comment made by the Coens in the July 2004 issue of Empire magazine: "No, that's never going to happen, sadly." Indeed it is sad.

In May 2008 I got my mitts on the screenplay. Download it here!

Ethan Coen now seems to be officially attached to this as sole scribe (as of March 2005) so we shall see what comes of it.

Apparently a remake of the 1966 British crime caper which starred Michael Caine as a suitable sticky-fingered thief who teams up with Shirley MacLaine to 'liberate' an expensive statue from its rich owner. Needless to say, things don't exactly go to plan and a series of double-crosses send the whole operation in to disarray. The Coen's version was originally rumoured to star Hugh Grant, but now Colin Firth and Ben Kingsley appear to have stepped in.

Potential star, Colin Firth, said this in September 2008 - “No! It’s a complete lie. It’s been on IMDB and just sitting there. The Coen brothers have written an absolutely brilliant script. [‘My Best Friend’s Wedding’ director] PJ Hogan came on and Ben Kingsley was attached to it. Then it was Sandra Bullock attached and then Jennifer Aniston. They [the Coen brothers] won’t direct it. It had a producer attached to it and no director.”

62 SKIDOO

According to Filmforce IGN this is a movie Joel Coen really wants to do. It's a cold war comedy and nothing else is known about it. There is also a small mention at the Independent's website.

Thanks to Stephen Glitheroe for the heads up.
A SERIOUS MAN

The very first mention of this one came in an Empire Online article on 24th April 2007. Simply confirming this movie as the Coen's follow up to Burn After Reading and that is was "a dark comedy in the vein of Fargo". That's it for now.

From Empire magazine's January 2008 issue as part of a 13 page Coen brothers feature; "Going into production next April (2009), little has been revealed about this comedy. Rumour has it as the story of a Jewish professor in the 1960's who starts to question the value of his life. He wants a divorce from his philandering wife, to stop his children taking all his money and to be rid of his deadbeat brother. Not only that, he is now receiving death threat letters from a mystery source, and his hot neighbour keeps sunbathing nude. The cast has not yet been announced, but various rumours have Jennifer Anniston, Colin Firth and Sir Ben Kingsley to feature."

MISCELLANY

Also during the promotional campaign for O Brother, Where Art Thou? in 1999, the BBC showed a 50 minute documentary about the Coen brothers. It was mainly concerned with the Coen's past and featured interviews with many of the actors that have worked with the Coens along with family, friends and crew members.

The most interesting part of this documentary for me, was a scene where a bookcase was shown (I think it was in the Coen brother's office). On the bookcase were around 40 screenplays that the brothers had written and not yet made. Titles included; Intolerable Cruelty (since made, of course), Coast To Coast (which is about a Chinese plan to take over the world using cloning which apparently featured 28 Albert Einsteins!), Voices, Chatahoochee, Leap In The Dark, Johnny Skidmarks (which was written by their friend and collaborator, William Preston Robertson and made into a movie in 1998 by director John Raffo and starring John Lithgoe, Peter Gallagher and one Frances McDormand), Meet Bobby Buttman, The Concierge (I don't know if it is or not but how excellent would a movie about Heinz the Baron Krauss Von Espie be?), Mr. Murder, Cult Cop, The Land of Youth, A Man In Shades, Justified Sin, Quark Victory, Red Harvest and Respect Your Godfather. No news on any of these unless stated I'm afraid.

 

"Don't know, Delmar- though the blind are reputed to possess sensitivities compensatin' for their lack of sight, even to the point of developing para-normal psychic powers. Now clearly, seein' the future would fall neatly into that ka-taggery. It's not so surprising, then, if an organism deprived of earthly vision-"- Ulysees Everett McGill, O Brother, Where Art Thou?