This probably isn't the typical Spoonflower shop -- these are the kinds of things I wish were in the fabric store when I was a kid, bored out of my mind while my mom was there for hours on end. My Etsy and blog links:
Daorgeron -- Spoonflower's options are to the right of the fabric image. The widths depend on the type of fabric you want, but the two basic cotton styles are 42" wide per yardage. There are also yellow ruler templates along the side of the fabric image to help you visualize it.