Wow, some of the replies to this post seem very 
bitter.  I can kind of understand being jealous, 
but ouch!  
There are a few cels of evil Tamahome at House of 
Anime.  I think they are a bit overpriced and not 
nearly as nice as the one you have, but those are 
the only ones I've seen for sale in a very long 
time.
In Ryouko's defense, she has sold some of her 
Tamahome cels in the past, and at the same price 
she bought them for- which is something almost 
nobody does- I don't think she's trying to "hog" 
them all.  Tamahome is my favorite character from 
FY, and it's taken me 2 years to get just 3 cels 
I really love of him- They are just scarce these 
days.