Last week I met author/illustrator James A. Owen and he told me about Every Picture Tells a Story, a store in Santa Monica California that sells artwork from children's books. I found all kinds of wonderful artwork, prints by David Wiesner, Mo Willems and David Shannon, but also a series of Mary GrandPre Potter prints I hadn't seen for sale before -- AND concept art from the movies. Now I have to figure out how I can afford one.
P.S. I am enjoying Owen's book Here, There Be Dragons, very much! He drew a dragon in every book he signed, and gives pointers on drawing them on his blog.