I gladly signed the petition, but i don't think it'll do any good. What with the rivalry between Dreamworks and Disney, I don't think there's much incentive for the two to work together.
Incidentally, I believe this was tried before. I worked as a tour guide at the Magic of Disney Animation at Disney/MGM studios Waaay back in 1998. On one of the computer stations that the animators were using for pencil tests was a bit of live action film with a man at a desk standing up with Roger Rabbit reacting to him. It was a short loop, left on the computer to compile, but it was long enough to see that it really was Roger. The rumor went around was that it was for the sequel "Who Drew Roger Rabbit," which was supposedly in production at the time. (Animators and Tour guides had very little contact -I was only allowed into the animation building once- so i was never able to confirm it.) And it's likely that any production that did happen was cancelled, as the projects the studio were working on at the time, Tarzan, Emperor's new groove (then titled "Kingdom of the Sun") and Atlantis have all long since gone out. In fact, a Animator's newsletter I grabbed when I went into the building announced that they'd just chosen the production team for thier new project, Lilo and Stitch. So, even though a Roger project would have a very long production schedule, it'd doubtful it ever got out of preproductions.