The only way I can see another TRON movie getting made at this time is for us, the fans, to make one. This surprises me since Disney is willing to make such toilet-floaters such as "Meet the Deedles" and "Cabin Boy". Even Disney's worst animated movies at least broke even or made SOME money.
Having said this: I'm announcing that I'm in a partnership with another TRON afficionado (goes by the name of Falty) to make a feature-length CGI TRON film. I've asked for some help in the Fan Fiction section of these boards, but I wasn't sure if it was one of those sections skipped by many readers of these forums, so I'm announcing it here as well.
I understand completely that since it's a work of love (Fan Fiction!), that it won't be TRON canon, but at least it's SOMETHING that's being done for us TRON fans. Regardless of how much help I can find for this project, Falty and I are determined to see this one to completion. It'll just go faster if we have help.