I have such a cel, but I don't want to sell it.

I'm not posting this in order to be mean, but 
rather to share what I've learned.

These cels are really hard to find.  This is 
surprising, considering how many episodes (96?) 
were made.  I once asked a well-known dealer why 
this was so, and he explained that there are 
indeed zillions of cels, but they have all 
disappeared into the private collections of KNO 
fanatics (like me).

What all this adds up to is -- your post here was 
probably EXACTLY the right thing to do:  try to 
flush the cel out of a private collection.

But you might need to keep it up for a while, and 
beat the bushes more broadly, to find one for 
sale or spring one loose.

Be tenacious....