[TAlholm]

I used to use polycarb or lexan as much as possible when making guards for components and other low stress structures. Although it didn't make its way onto 1991's robot, this past year I had made a sturdy scissor lift out of lexan and plastic bolts. I believe the weight of the scissor lift itself was between 1 and 2 lbs. Granted, the entire climbing mechansim was over 5 lbs.
Polycarb and lexan are very strong, and after talking with 4061 (I believe) at worlds, it makes a good amount of sense to use it for arms of an intake or other extending components. Mainly due to the flexibilty of the material, and unlike aluminum it usually goes back to its original shape.

(Just be sure to use lexan or polycarb, and not acrylic. It ends poorly if you try and bend it)