Find a local fabric/haberdashery store - You should be able to purchase a yard or two of velvet (or other suitable material). Take the opportunity to chat to the staff, and chances are, you'll find one that is happy to put a hem along one edge.
Originally Posted by Jim Cole
Thread a length of 1/8" elastic cord through the hem and then use a spring toggle to adjust the tension to suit.
You might find a mom'n'pop curtain store will also be able to oblige for a minimal fee - Say a print of the store and staff