Michele:
Thanks for your suggestion. I have definately considered doing that. I am trying to find a new quality source locally for transparencies, scans, and the like. The source I used before has really dropped in quality and I had to have them redo my last painting twice before they got it right.
I actually have a clause in my contract that says that I can borrow the painting back for shows every now and again and that the client will make reasonable efforts to get the paintings to me. This worked well just this weekend when I borrowed back four commissions for a big show here in Denver. Actually, many people are thrilled to have their painting in a show.