[Al Skierkiewicz]

Patriot,
If you are only going to require the tube to move a few turns in one direction and then the other, you can pre load the wire so that it has enough length when it is at the midway point to turn in either direction. You must limit the rotation so that you do not exceed the length of wire. You can also run the wire down the inside of the tube. The PWM cable can stand a fair amount of rotation over the full length of the tube without failure. Perhaps as much as +/- 5 turns especially if you use an extension PWM cable. Please remember that you can use surgical tubing to hold the wire out of the way if needed, up to the specified size please.
If you require continuous rotation, then I will have to think about it for a while. Nothing in the rules that I can think off would allow you to continuously rotate the tube. If you would care to PM me, I might be answer better off line so that you don't give away your strategy.