I have found some information, so I thought I would share for anyone else who may find my post:
Most of the light pipes are made from a clear acrylic or polycarbonate "optical grade" plastic. I have ordered some cast acrylic and polycarbonate so I will report my results.
I have found a link to a good pdf detailing light pipe design:
I need to find a way to diffuse the end of my lightpipe. Maybe the cutting can do it itself, I dont know yet.