Are there many quilters/sewers in the surrounding community (besides those of you in the guild)?
If not... then you might have trouble getting anyone other than guild members to come to the show.
But if there ARE a lot of sewers/quilters... perhaps you could do raffles or silent auctions on supplies. Like, maybe, raid your collective stashes and everybody brings in four FQ's that they can bear to part with, and you could re-combine them into, say, groups of 8 that are related, and tie 'em up with a pretty ribbon.
You just KNOW that everybody else's scraps are more interesting than your own... :-)