Museum quality really is the only reliable way to go for displey, i agree
and its not as expensive as you might think...go ahead and buy the frames
from target, _but get the glass changed_ and put acid free backing between teh cel 
and the cheap backing. (i would pay to have the cel mounted professionally)
average size for the glass ends up being maybe 15-20 dollars, possibly cheaper,
and really does a better job allround.
my two cents worth :)
mandy