That's all the Dragon Half cels I've seen, too.  
Makes you wonder where they all are.  Sure there 
was only two episodes, but still.  

I wonder if there is some rapid Japanese fan who 
cornered the market on these and has binder after 
binder of nothing but DH cels.  :-)  I've heard 
stories about some collectors who specialize in 
certain shows and have rooms filled with binders 
that represent almost every cel from certain shows 
or episodes.  The few cels that we see floating 
around either got away from them or were sold by 
them.

It honestly wouldn't surprise me.  Think about how 
many cels go into making just one episode of an 
anime.  And think about how many collectors can't 
find certain cels after years of searching.  Ah, 
the mysteries of life.....

JP