Some more ideas for collecting cels...
-- Back in the 1970's and 1980's, my family purchased a few production cels from several private art dealers. You can find advertisements for many of these dealers in the Tomart's Disneyana magazine (that comes out monthly or bi-monthly, I'm not sure which). A couple of these dealers also advertise in the Disney magazine. You can also go on the Internet and simply do a search for "Disney animation cels" or "Disney animation artwork" to find more dealer sources.
-- At least one big New York auction house usually has several animation auctions every year. If an auction is big enough, or theme-based, the auction house may even publish an auction booklet that describes all of the pieces being auctioned. Right now, Sotheby's is the only auction house that comes to my mind (I don't know if Christies' is still in business) . The Tomart's Disneyana magazine mentioned above usually has one page in each issue in which it summarizes the latest auction results for all major auctions held recently. This page would be a good place to get names of auction sources.
-- Of course, there are also the online auction sites, such as e--- .
-- The
Disney Store's printed and online catalogs occasionally advertise LEs and sericels.
-- You can try calling the "Art of Disney" stores at WDW and the "Disney Gallery" at
Disneyland to see what they have on hand. These places most likely would have just sericels and LEs, not production cels.
Hope these ideas help... collecting cels is a great hobby, especially when you find a cel of your favorite character in a great scene from a film that you love!