A sexually frustrated London circus dwarf has a one-night stand with the depressed, childless wife of a circus magician. The dwarf quits the circus and retires to a small northern town, waiting vainly for the magician’s wife to join him. Eight years later, she turns up on his doorstep, announces that he has a son, and rushes away. The dwarf pursues her, but dies of a heart attack at her feet. To the gathering onlookers, the magician’s wife announces that her son died a few days ago.That's the basic plot of Vladimir Nabokov's unproduced screenplay The Love of a Dwarf, listed by Salon.com alongside six other unproduced gems by famous intellectuals (including Jean-Paul Sartre, Aldous Huxley, and Georges Bataille). The article focuses on unusual and surprising ideas or collaborations, but I am certain there are countless other screenplays out there (or lost between the sofa cushions of time), written by celebreated authors, which remain unproduced. Just think of all the worthy novelists - Faulkner, Fitzgerald, Dalton Trumbo, et al. - who at some point turned to Hollywood for steady income. The studio system at the time was very much like a production line attempting to churn out fairly homogeneous products, so that a lot of screenplays were completely reworked by directors and executives, or never came to fruition (I guess the situation today is similar; at least back then writers had a regular paycheck).
Barton Fink, yet another writer of unproduced screenplays
I don't know enough about the topic to make any far-reaching claims regarding the quantity of unproduced screenplays, but I assume it's quite a pile. Anecdotally, I can present the case of Nathanael West, who worked in Hollywood for about seven years and contributed to 28 treatments and screenplays, of which 10 were never produced (some never made it past the treatment stage). Though I can't vouch for the quality of these texts (which is probably the case for the vast majority of unproduced screenplays), there's at least one that's worth mentioning:
In 1939, Nathanael West and Boris Ingster were asked by RKO to write a screenplay based on Francis Iles' 1932 novel Before the Fact, but when the film was assigned to Alfred Hitchcock, he already had his own substantially different screenplay, which he filmed under the title Suspicion. West and Ingster's screenplay was abandoned and never produced, though it's included in the Library of America's edition of West's collected works.
It's up to Hollywood historians, Faulkner faithfuls, Fitzgerald fanatics, and others of their ilk to dig up these lost artifacts and bring them, if not to the big screen, than at least to our computer screens. Certain famously unproduced screenplays, Like Nabokov's Lolita and Harold Pinter's Proust Screenplay have already been issued as books, so there's obviously some interest in these. Even if they're not the greatest works of literature, I believe these screenplays still have value; at the very least they could reveal that even Nobel-prize-winning authors like Faulkner could produce clunkers, a small bit of comfort for us - the petty and the unpublished, The Unsound and the Furious.