Have you considered buying Mirror Card and cutting it to size?
Yeah, as well as Mylar with a hard backing and Acrylic mirror stock, but in the end I feared that it mught be impossible to aim reflected light where one intends due to warping. However, it's an idea I'd really like to test, and if I had the time to do see how well it worked I'd go for it.
Thanks for the idea though! All input is greatly appreciated. <img src="/images/graemlins/smile.gif" alt="" />