How about making a string quilt out of the clothes? That way, each strip will be sewn to a muslin backing and you won't have to worry so much about the different fabrics, plus it's a style that lends itself well to scrappy fabrics.
Something else neat to do is to again, sew the fabrics in strips onto a muslin backing, then cut the "new" fabric out and make memory bears... teddy bears out of it.
http://www.quiltville.com/stringquiltingprimer.shtml