We are currently using an intake that involves surgical tubing connected to a rapidly spinning hex shaft. The intake works well (moderately), but we've started having some worries about its legality per R8 and R9. The flails aren't extremely dangerous (they hurt while spinning, but don't cause bruises) but sound pretty loud.
An example of it in action can be seen here: (we're the robot with long arms)
https://www.youtube.com/watch?v=T3Q2...ndex=1#t=0m37s
You can see a closer view of the intake (not on) here:
https://www.youtube.com/watch?v=mc16NglqYuM