I mentioned this one before, but I ordered a 
Washu w/ BG cel from Anime Taro.  I didn't even 
know it was multilayer until I got it in the 
mail.  The 3-layered cel was in a bag by itself, 
separated from the BG.  Inside the bag, the 3 cel 
layers were separated by layers of (cheap) 
polyethylene (which I replaced later).  This is 
one of the few unstuck, multilayer cels that I 
have.

I'll have to scan each layer one of these days (I 
think I have to rescan anyways since the 
alignment is off compared to the DVD screen cap I 
made.)