Chevymall.com does have the lithos (unsigned) to buy...they are slightly different from the ones Mike uses. They don't have the Oshawa logo on them. Those were passed out to employees the first day of production.
If anyone organizes something to thank Mike let me know I would like to contribute. A litho may not be they way to go...He may have seen one too many of those by now! Maybe one of the books from CamaroFest?