Speaking of Akira, The Seven Samurai should be left right alone. Akira Kurosawa was a genius of a filmmaker and Samurai is right up there with The Godfather - funny, engaging, with brilliant fighting scenes, watchable any number of times. No chance of getting close to it with a remake, and no way by just emphasizing the man-on-man fighting.
Westworld would be very interesting, in an updated version with new technical horizons. I've heard about the project before, thought it had been shelved due to contract problems. The 1973 film is very good.
A reboot of (or "film inspired by") Stalker could come out quite good, if it were made by the right director and actors and in the right place. I love Tarkovsky's original, seminal film, but in this age of post-disaster, post-apocalyptic stories it would be very cool to see what could be made of the concepts of that film now, even though Stalker wasn't centrally about the disaster or the rundown town and the deserted zone (I'm also planning to try the Ukrainian PC game which was inspired both by the film and by the Chernobyl event - have wanted to play it for a long time but didn't have a computer that would support it)