Here's a video showing our competition robot with a lot of footage of our ball control mechanism. As you can see the primary components are rwo FP motors coupled to two Banebot 20:1 gearboxes powering two Banebot 3 7/8 wheels. The mechanism also has a way (ram light) of telling the driver when he is in control of a ball. The driver controls the mechanism via a second stick (left) on the control box. That stick also spins the robot left or right to aim. We have a practice robot with the same mechanism installed. The past few days the driver has been practicing ball control by keeping a person from being able to take the ball away from the robot. The mechanism works very well and we're anxious to see it in action on the playing field. Here's the video
http://rambotics.com/video5.html