There were rumors that they were going to work on a ps3 exclusive after the Okami Wii port. I'm not sure how credible they were.
Edit: Actually, the rumor was that they'd be developing the next J&D for the ps3 instead of Naughty Dog. I would consider it 100% false, then, as Naughty Dog loves J&D, and have expressed interest in making another one, and I can't see them giving up the franchise.