Blade Runner The Game (by Westwood, 1997) is an awesome game.
Unfortunately Westwood is gone, and I think EA has the rights (if any currently).
The annoying thing is that the game does not run well on modern systems, it's 4:3 aspect limited, pretty much resolution locked as well.
If Obsidian used the game as guide/blueprint, kept the story/plot/characters (i.e. "the script"), used a modern 3D capable engine and taking advantage of current tech, it would be a fantastic game.
Alternatively approach Ridley Scott and use the old Blade Runner game as a example of the game/style a new game should have,
I'm sure they'd be happy to be in advisory role, Ridley might even be interested in being more involved which could mean a nice starting budget as well.
So either a modernization (I'm trying to avoid using the word "remake" here as they rarely are true to the originals),
or a brand new game with a new plot and story but in the same style as Westwood's game which is probably the best movie-to-game "adaptation" I've seen.
And why Obsidian? Because KoTOR II, Alpha Protocol, and New Vegas has shown that Obsidian can handle "dynamic" intricate plots like that of the Blade Runner game.