What are the wizards at Pixar working on at the moment? ...aside from finishing up "Toy Story 3", of course.  How about a mysterious project involving a little boy and a big Brontosaurus?  If an all-too brief glimpse of some early concept art on display inside Pixar's studios is any indication that would seem to be the case.  Hit the jump for the sketchy details.

A sharp-eyed Pixar fan recently wrote in to Pixar Planet to point out some intriguing artwork in the background of a publicity photo.  The picture in question shows studio sculptor Greg Dykstra working on a clay model of Carl from "Up" but just over his shoulder, hanging on the wall, are some shots which appear to reveal designs for a previously undisclosed project.

The top picture shows a bronto-like dinosaur, while the second and third feature close-ups of an unknown young boy.  When asked about the artwork on Twitter, Pixar's story supervisor Ronnie del Carmen responded that he did know the origin of the concept art, then added:

"But not telling. Nothing to do with anything 'Toy Story', tell you that."

As Peter Sciretta noted on /Film, the art doesn't look like it fits in with "Newt", the studio's feature about the survivors of a reptilian species known as the blue-footed newts, which is due out in 2012.  So my guess is that the pieces are for one of Pixar's infamous short films - the ones that the legendary animation innovators use to hone their skills and break new ground in the business of computer generated animation.

Click on the image below to see it embiggened.  And chime in: what do you make of these mysterious designs?