Salon features this article from Elif Batuman on unproduced screenplays by famous writers, politicians, and thinks such as Vladimir Nabokov, Winston Churchill, and Jean-Paul Sartre. I found this possible screenplay by Georges Bataille interesting:
In 1944, the French writer and philosopher Georges Bataille, the so-called “metaphysician of evil,” decided to write a “commercial” film starring Fernandel, a singer-comedian particularly famous for his horselike teeth. In a departure from earlier roles, Fernandel was to play a bourgeois Marseilles soap manufacturer who, during his children’s holidays, assumes the costume and character of the Marquis de Sade. With the participation of some local prostitutes, he reenacts the practices described in “120 Days of Sodom,” Sade’s novel about four scientific-minded libertines who lock themselves for months in a medieval castle, subjecting forty-six innocent young people to escalating sexual torture, culminating with murder. When the soapmaker’s experiments likewise result in the death of a prostitute, he commits suicide, effecting “the triumph of morality.” After approaching one producer, who was not encouraging, Bataille abandoned the script, which has been lost to posterity.
This is a fundamental difference between literary or intellectual pursuits and film; cinema inherently limited in its ability to present complex ideas because it has to do them visually and aside from experimental or art house cinema, it is difficult to find audiences or even funding for high minded projects.