Most, if not all of us now know what motors are available.
I just hope that one day FIRST get's in touch with NPC Robotics
http://www.npcrobotics.com/
Yes, the do affiliate themselves with combat robots(not the issue, so don't start that war)
They have a wide variety of high quality parts that are strong and should handle about anything we could throw at them.
A few highlights-
http://www.npcrobotics.com/products/...at=19&mode=gfx
http://www.npcrobotics.com/products/...at=20&mode=gfx
Yes, a lot of their motors are designed for 24 volts(some even take 72v with some work-
http://www.npcrobotics.com/products/...at=20&mode=gfx)
The gearbox/motor/wheel combo in the first product link seems fairly close to optimal for the direction the kits seem to be going.