I feel your pain!  I fell in love with Rose of 
Versailles a while back and have been scouring the 
world for cels since then.  I'm afraid to even 
watch Oniisama E, in case I start wanting those, 
too.  :-)

For Rose of Versailles, have you tried Anime Taro?  They 
have a number of reasonably inexpensive cels of 
Oscar up at the moment.

Darn it, I don't seem to have the picture I wanted 
to post here on my machine at work.

--Atiya