Find local longarm quilters, contact them and ask their (policies) concerning donation quilts- you just might find one willing to donate the quilting- you just pay for thread, or someone may give a reduced rate. You should know ahead of time what the costs may be before discussing with your group, so you all know what the options are. I generally do not charge for charity quilting, only for any supplies needed ( if I provide backing or batting I charge for cost of those) or if it is mailed the postage is an expense. You may have a local quilter who will happily do the job