I sympathize... I feel the same way sometimes 
too. Of course, I did that to myself... in 
collecting only a single series that's not 
tremendously well-known in the English speaking 
fandom. ;) 

Of course, that means that there's not rabid 
competition for Hunter x Hunter cels, and 
they're not hugely expensive. (Not for the 
characters I collect, anyway. *snoogles her 
portrait shots of Gon that cost about a quarter 
of what a similar cel of Killua or Kurapica 
would have cost*)