Watch for a clearance roller shade in the size you choose. One with a continuous loop cord would work better than a spring roller. Remove the fabric from the roller. Replace with either batting or felt or a vinyl table cloth. The roll when up will be thicker than the original fabric but should work the same. You just have to make sure you have the depth to accomodate the size by extending the brackets out with spacers. You might also have to stitch something along the bottom as a weight bar to help hold the fabric down and make the unrolling a bit easier.