This is probably best for circular table cloths on round tables. I'm sure some of you out there will find a way to use the technique in other ways as well.
Condition some polymer clay in a color that blends well with the main color of the fabric. I would recommend using only natural fiber fabric, that is no polyester blends. Cut a circle of fabric slightly larger than finished piece. Put the polymer clay through a pasta machine until you get a smooth, thin sheet. Lay your fabric over the clay and run the whole works through the pasta machine again.
Carefully cut the clay/fabric to the finished size. Drape this over an oven proof form such as a small glass jar or wood haps and bake as usual. I saw this idea in one of the dozens of books I've read on polymer clay.