Using some of the suggestions already given, you could maybe buy the heavy fabric you want (lightweight canvas, duck cloth, home dec) in the home dec section of your local fabric store or online, make a pocket along the bottom edge for a dowel rod to give it some weight, then sew a piece of Warm & Natural batting to the back so that side would be facing out when unrolled. I think I might sew a few parallel lines of quilting so the batting doesn't stretch over time. Just a thought!