Gordon
http://www.gordongrid.com
FRP sheets & diffusers.

USG
http://www.usgdesignstudio.com
Translucents, PETG panels contain 40% recycled content.

Nudo Products
http://www.nudo.com
FRP

Sequentia Products
http://www.cranecomposites.com/sequentia
FRP smooth, textured.