Its an interesting thought, and I guess its more likely now, assuming the acquisition goes through. But Disney has stated they have no near-term plans to build another domestic park. It doesn't appear that DCA and AK acheived the kind of financial targets they were looking for when they built them, and they have stated new parks, and even big new attractions will not be their primary focus in their attempts to grow.
If they did build a new park, I guess a Pixar theme could be made to work as well as anything else, but the primary issue would be getting past the idea of it being a kiddie park. Even DL/MK aren't solely based on Disney's animated films. I think a full-fledged "land" would be more likely.
But as Kae said, there are already some Pixar attractions in the various parks.
Buzz in MK and DL.
Its Tough to be a Bug in AK and DCA.
Turtle Talk in Epcot (was this also added at DCA?).
Monsters Inc in DCA.
Finding Nemo Sub ride coming to DL.
The Pixar characters have also been featured in various shows, parades and meetngreets.
Its true, there aren't as many as you might expect given how successful the Pixar films have been. My guess is that's at least in part because of the delicate nature of the relationship between the two companies. Now that the relationship is apparently going to be solidified with the acquisition, we might start seeing more Pixar rides in the future. And hopefully they'll be good ones, with Lasseter apparently having some input/control in that area.
