Thanks for the replies.
I suppose I should share my own teams collector:
It is a 16" wide 5lbs hinged roller claw. We use polyurthane belting to drive each of the four rollers (on dead axels) and to cover the front rollers to pull the tubes in. The top is basically aluminum angle and the back and bottom are basically polycarbinate L's which are forced open and closed via pneumatics. The front two rollers are made of polycarbinate tube and the back two are thinwall aluminum tubing. We also have a limit switch attached inside the claw to sense and automatically pick up tubes to minimize pickup time and make it easier for the drivers to pick up tubes without being able to see.
Overall, we are very happy with it. It can handle both over-inflated tubes and under inflated tubes well, and allows for both quick and inaccurate ground pickup and scoring. As an added bonus it is very low maintance.
This is a pretty good look at it and how it functions
http://www.youtube.com/watch?v=jeUBHoelq4o about 2:00 minutes in.
I would love to hear from other teams what design process they went through to end up at the claw they did. It seems every team came up with their own unique solution and implementation.
Thanks again, Bryan