Team 93 used fiber glass impregnated plastic last year on our upper frame. It worked out really well, only one piece of it ever broke. To attach it to other members, we milled down a piece of structural aluminum to a press fit inside the fiber glass and tapped the hole of the aluminum.
If you have any more questions about out technique, feel free to e-mail me:
ryan.brandenburg@gmail.com.
GOOD LUCK
-Ryan