Sarah-Sensei's Ramblings

Does anybody out there know where I might find a few pictures of old video game concept art (particularly of the 8-bit Nintendo era?) I have some old manuals and I may scan those, but I'd much rather have more sketchy stuff like doodles with notes and sketches-- more like the fare you'd find in an art book. I'm working on a lesson idea about video game art for the end of the year and it'd be sweet to do a sprite vs. hand drawn comparison to some of the early stuff. I'm mainly focusing on the art of Shigeru Miyamoto, so Nintendo stuff is preferred.