That said, this doesn't mean that Pixar is going to make another feature-length sequel for the franchise. It just might mean that Tim Allen, and some others in the cast, signed up for multiple films some time ago.
However, with the recent success of Toy Story 3, Disney and Pixar have to at least be thinking about a fourth film.
"We are thrilled with the audiences response to Toy Story 3, and fans will be seeing more of the Toy Story characters in a short film next year. At this time, we have nothing to announce regarding another full-length feature." Stated a representative for Disney.
"Bring it on."
Should a story on this develop further we will be sure to bring all the information to you.