You can also give your muslin backing a great look by simply dying it to match your projects. Dye comes in easy to use liquids now and you can go for solid, tye dye, streaky, twisted and lots of other looks.
Another great look is the tea/coffee dyed one that I love. Muslin is easy to dye in the washing machine or outside in a tub or bucket when cut to size. Do allow extra for shrinkage tho. Tea and coffee dying can be done right in the kitchen sink. There are lots of natural dye plants if you want to play with them; onion skins are another fun one. Check out books at the library on it. Muslin is a great fabric for all of these methods.