Hi, I am not sure if was mentioned before on the 
forum, but I thought I'd pass along the 
information just in case it is helpful.

After a little poking around on Google, I found 
this framing accessory store:  
http://www.americanframe.com

They have a wide-variety of acid-free mattes, 
frames, acid-free foam core and UV protectant 
plexiglass.

There is even an option where you can 'build 
your own frame'.  All you need to do is pick out 
your frame, plug-in your cel size, choose your 
colors and matte preferences and it measures 
everything for you for your matte, foam core, 
frame and plexiglass.  I found it to be 
extremely helpful for those "odd-sized" pan cels 
that I can't seem to find a normal frame for. 
The prices were reasonable, IMO.

I just ordered from them, so I can't vouch for 
their service/quality just yet.  I can let you 
know once I get everything.

I just thought I'd share this with you.  ^_^

jINx