I usually do some piecing on all of the backs of my quilts. I like the way it looks, almost making it reversible. And, I read somewhere that including some pieces of various fabrics from the front on the back will also give fabric for future repairs of the front if needed. Here are a few examples of some of the backs of quilts I have done that may spark an idea for you:
[ATTACH=CONFIG]544744[/ATTACH][ATTACH=CONFIG]544745[/ATTACH][ATTACH=CONFIG]544746[/ATTACH][ATTACH=CONFIG]544747[/ATTACH][ATTACH=CONFIG]544748[/ATTACH][ATTACH=CONFIG]544749[/ATTACH][ATTACH=CONFIG]544750[/ATTACH][ATTACH=CONFIG]544751[/ATTACH][ATTACH=CONFIG]544752[/ATTACH][ATTACH=CONFIG]544753[/ATTACH]