It would be easier, and possibly more profitable, just to have a garage sale with the donated fabric. I know I am more likely to buy yardage than to buy a kit, especially one that is put together with odds and ends.
Fund raising is the bane of all guilds IMHO. It's necessary, and I admire the members who do it willingly and try to come up with new ideas. My guild has so many different fund raisers - opportunity quilt (raffle), brown bag as described by GingerK, silent auctions for the more desirable items during the brown bag event, annual quilt show where quilts are auctioned and handmade items are sold, various raffles for prizes during meetings. Most of the money goes to philanthropic projects, but we also have speakers and workshops a few times a year.
Another thing that might work is to ask businesses in your area to donate items. Restaurants are often happy to give out gift certificates for worthy causes, theaters will donate tickets, etc. You can put together some nice baskets with a variety of items and either do a raffle or a silent auction.