I have seen cels from all of those shows up for 
sale in the last couple of years - but not very 
many or very often.  Definitely check w Van Eaton 
like someone suggested.  Also a private collector 
sold some of his D&D cels about 1.5 years ago I 
think so there is always a chance those will come 
back up for resale (there was a Sheila, Eric and 
Hank that I remember).