A good frame shop should be able to make a custom 
frame for any cel regardless of size. It may cost 
you a pretty penny, but it's worth the money. I 
have an over size Spriggan cel that is about 
12x19, and it came out very nicly when I got it 
framed. The frame itself is about 16x22, and with 
acid-free amts and UV protecive glass it came out 
to about $140. And if you get a your cel 
professionally framed then I wouldn't keep the 
cel in a bag.