Asside from framing (which you've already said isn't really an option - and I have to admit, I sort of assumed it wouldn't be!), I'm not sure what other 'damageless' options there are. The suggestion about talking to a colonial house museum or somewhere like that's probably the best bet. Or, though it's a long shot, you could try a costume museum - though they probably don't display quilts, they do have some ideas on how to preserve fabrics.