The same should be also true of Cowboy 
Bebop and Utena, two series for which 
cels, even low-end ones, are notoriously scarce 
on the market.  It is certainly true that there 
are a lot of low-end CCS cels ... butt shots, 
arms, closed-eyes, stuck-to-sketches, etc.  And 
it was a long series.  But one would expect there 
to be a lot of Utena butt-shots, etc.  
That suggests that, on some level, an 
Utena butt-shot is seen as more 
intrinsicaly valuable than a CCS butt-shot, and 
so it's rarely seen on the market.  

Or did some enterprising person buy up all the 
Utena butt-shots and destroy them?