Hi all, I had to go to the art supply store a few 
days ago to get some prints made, when I saw the 
most awesome thing!  It was a very large 
portfolio looking item, only it was obviously 
made for very few peices of art.  There were no 
sleeves inside I think, just a dividing sheet.  I 
also think you could close it securley.  It was 
clear and had a handle on it.  I think this would 
be awesome for oversized cel storage!  The ones I 
saw were made by Daler-Rowney.  You may want to 
check the web for some of their supplies :) If I 
ever get anymore huge cels I will definately be 
picking one of these things up!  Thanks!