We made a suction system for the 2008 game, FRC1771 did also.
You can see a modified version used in our quick video from this year:
http://www.youtube.com/watch?v=3FyQQt_3u0Y.
This is a banebots 550 running a shop vac impeller. The seal is not ideal, as we just ripped the weather stripping previously used at the edge to form a seal around a smaller circle in the cone. The cone is also not shaped to this size ball.