The Fallout wiki has word that they have received a Fallout film treatment from the Brent V. Friedman who wrote this second revision for a now-cancelled movie that was being planned back in 1998 before the release of Fallout 2. They offer the full treatment in Adobe Acrobat format as well as this summary of what it includes. Here's their general abstract:

The movie was not a faithful adaptation of the game's plot, and was never intended to be one, although the main story was loosely based on that of the original game. Some of the elements of the Fallout universe that many players can't imagine a Fallout title without, like ghouls, Brotherhood of Steel, deathclaws or power armor, were not included, although it's understandable given that e.g. the BoS is not as essential to the plot of the original game as to the later ones. The only characters from the original game, aside from the Vault Dweller himself (although here we have a party three vault dwellers - aside from the main Hero, there's the Female Officer, Techy and Scholar), are the Overseer, the Master and Dekker - the movie was to focus on Vault 13, the search for the water chip and the super mutant threat, and most other parts of the game did not make the cut. New characters and threads include Max (based on Mad Max), the hero's Intended and his relationship with his father (which may sound familiar to fans of Fallout 3).