Hello,

The cels do show up from time to time and Yahoo 
Japan has some posted every now and then.
Just takes a little patience.
You could check with Mandarake possibly, I bought 
a nice cel on their auction, it's on my site if 
you want to take a look at it.

Cels of the little girl Setsuko are the hardest 
to find. 

I believe Totoro came out about the same time but 
it's not too hard to find Totoro cels, Grave of 
the Fireflies cels are hard to find.  Maybe it's 
the subject matter.  

w.b.