[WizenedEE]

Wow, that actually sounds really cool.

The problem would be getting the claw back down. You really don't want to rely on gravity, and there isn't really a spring that would provide a constant force from 8' to 6"

You could have a second motor used to pull it down, and be very careful not to let the two out of synchronization.

It also doesn't look like you'd need to be able to rotate the tube, although it may be helpful. The problem is that it's a lot of motors on there -- two to rotate the rollers and another to rotate the entire claw. Then another three for movement of the entire thing.. that's six motors, assuming you don't have to double up on anything.

But again, it's a really neat design, and it may just work.