Balancing may not be as difficult as you think it will be. Check out this:
http://youtu.be/-AMaqqmoLgQ?t=1m27s
28 inches away from center and 2 batteries on one end will still be balanced. I'm sure all of you know, those batteries have some weight to them also. So, balancing may not be too difficult though getting 2 bots on it at the end of the match quickly may be. Especially from opposite ends of the field being both bots getting on from each end instead of one following the other on directly behind.