i dont imagine these would be hard to make.   in high school shop class, we
made various objects out of "lexan" plastic, by shaping it in forms heated in
a oven. some kids even made tinted headlight covers. i made an ashtray (good
idea, chris, a plastic ashtray.. ;<)   If you get some good quality plastic
(comes in all different colors, as well as clear or smoked)  i bet you could
make these yourself, using a simple wooden mold, in your own kitchen oven.

chris