You can always pop out the glass on these frames 
and pop in UV glass that you buy at the local 
artstore. You can also pick up the acid free 
matting at the artstore and sort of frame it 
yourself in the less expensive frame. The frame 
store by me even has special frames that you buy 
in standard sizes and are meant for just this 
kind of self framing.

If you have an odd sized cel, you can even buy 
the frames in pieces and assemble yourself. 
Personally, I'd rather just buy the bigger frame 
and have them cut the matting to make the 
cel "standard" size.

This works great as you can store your cels in 
the cel book and then let them take turns being 
on display. You also don't have to worry should 
you ever want to sell one that you won't be able 
to recoup the cost of framing it (b/c you 
probably won't).

For the more expensive cels, and the ones they 
will "never pry from my cold lifeless hands", you 
can still get the framestore to frame museum 
quality. The store by me charges $160 - $200 to 
frame, so it's only for those very cherished cels.

hope this helps!