On February 1, 2013, the Pixar News website posted an image of what may be the logo for Bob Peterson's forthcoming (May 30, 2014) feature release. Pixar News is reporting that they received an anonymous email from a reader with the logo included.
On December 31, 2012 the Coming Soon website received a foldout card from Pixar studios which included artwork for four upcoming Pixar films - with one of those being The Good Dinosaur. Although the dinosaur in this logo does represent the dinosaur in the concept art Coming Soon received, we still can't be positive of the validity of the logo at this point.
For reference, it should also be noted that on April 25, 2012 during CinemaCon, John Lasseter first discussed The Good Dinosaur. During his keynote, John displayed the image below to discuss the then-untitled project.