I would say that if you are serious about entering it in a contest for art quilts, then quilt a new back however you want that back to look, and attach it to your quilt,hiding the back you have now. You will need to work out the problem of the sides - will you birth it? or take off the binding and replace it? Since it is an art quilt I can't think that the fact the quilting on the top and back do not match will be anything but a creative, artful decision on your part. however, you might want to query the entry rules of the contest you plan to enter. You could have a reversible quilt. Scenic one side, whole cloth trapunto on the other. Good luck!!