Most feature film productions give exclusive gifts to the technicians that work on the movie. These are commonly known as crew gifts. For people working on Revenge Of The Sith
, Lucasfilm gave, among other things, a very cool Chewbacca maquette
. You can see one of them in the auction linked above, which is in its final hours as of this story's publication. Do note that these were originally presented in white boxes with a red ribbon and a silver oval sticker with a red LFL logo printed on it. If you want a great conversation piece in your collection, you need to check this auction out before its too late!