While not a movie, and probably never will be a movie, there is a book titled Lost Boys by Orson Scott Card that has a computer programmer for one of the main characters. The character wrote a successful game for the Atari (I don't recall if they say specifically, but I'm pretty sure it's talking about the 400/800, and not the VCS), and at some point there is talk of porting it to the C64, and eventually the IBM PC. I think it's a pretty decent book, a little weird in some parts.