Lou Romano has lent his voice talents to several Pixar movies, including Ratatouille, in which he played the protagonist Linguini. He's also one of Pixar's artists, and he recently posted some production sketches he worked on during the development of Up, which grossed $68.2 million at the box-office during its opening weekend (third all-time for the studio behind The Incredibles and Finding Nemo).
Check out Romano's blog for the complete gallery.