Our team actually succeed doing the kick with one motor...
Probably will work with the FP motor. but still it is working with one motor and some springs, and can be also adjustable to the distance we want to kick the ball to.
The hard part in the mission this year is not just to kick the ball far, because you don't need to kick it more then 50feet and about 3-4feet in the air at the highest point. The hard part is to make your kicker adjustable so the kicker operator can adjust it to kick in different distances, for example if you are in the other alliance zone and moving to the midfield so other robot in your team can get in to defense you need to kick the ball 10-25feet less, so if you will build your kicker to kick the ball for 60-70feet and kick a ball from the midfield your ball will just bounce back to the midfield if not go out of the arena. Not to mention that if you build your kicker to kick even for 40feet you will most likely won't be able to get a ball into the goal unless you do it from the midfield or something or just push it to the goal. So teams with a really good kicker design that can adjust the distance the ball goes will most likely be "Wanted" because they can basically play in every part of the field without any problem.
Try thinking of that, i won't give you how the whole kicker works, but you can take guesses and a pic will probably be posted after the regional. (Or you will see the robot on our YouTube channel:
http://www.youtube.com/user/Team2230 )