Van Eaton Galleries has got a ton of cels from
just about anything imagineable...except anime! :)
They are located in Sherman Oaks, CA, so if 
you're in Southern Cal, go down there and be 
amazed! :)  Their website is 
http://vegalleries.com and the www site does not
have thier whole stock.  If you are not in 
Southern Cal, give them a call and ask what they
have.  They are very nice and professional.  If
it was done with cels, chances are they have it.
Check my www site in the Western Animation 
section for a NIMH cel and a Brown Hornet cel I
got from them recently.  Expect to pay in the 
$300 range for a good P&B cel.  Good luck! :)

Jen