Instead of entailing yourself in all the work involved in a quilt show, have you considered a quilt raffle? Years ago when my children were in a small, local drum and baton corps, I also took part in our fund raisers. One year I offered to make a simple patchwork quilt to raffle off. I used a lot of my stash, donated the backing (just used muslin) and the batting, made a twin-size quilt (just simple 5" squares) and tied it (at the corners and centers of each square. It looked so old-fashioned and was so cute. For several weeks we sold tickets outside grocery stores and small shopping centers (with permission, of course), held the raffle drawing at one of our band practices and a teen-age girl won. She was thrilled. We made over $350 which we thought was great. As I said, this was a long time ago and that was a lot of money then.
If you could get donations of fabric scraps, batting and backing, it need not cost anyone very much money. If you get volunteers to cut out squares (or other shapes), arrange them in a pattern and have everyone do a little sewing, you could be finished in no time. All you would need is a little time and you could make a few dollars for your church. Three churches, three groups of volunteers, three quilts, three times the profit!