The Spirits Within is based on FFVII, obviously. It's not word for word the same story, because people at Square are smarter than that.

I'd love to see another FF film in the same style as TSW. It was a masterpiece. Unfortunately, this is the time of sequels, prequels and remakes. Most people don't want to try and understand an original story, they want the same story over and over again.

No FF story could be translated into a film. Even if you were willing to watch an 80-hour film, it would be crap. Imagine one of the actors shouting "Curaga", or a party of three on the back of one Chocobo.