yah, 60 amps continuous discharge, thats like 12hp, and a PITA to charge. Would be a good fit for the citi car if you can sort out charging (and ~48v is going to be easier to sort out nicely for nimh). According to this, the problem with parallel charging is the different resistances
How to charge Nickel Metal Hydride Batteries tutorial for design engineers.
So maybe you can measure the resistances and match them up 3 wide for the c-car? or live with a 10 hour charge?
Hope you beat the $2.50/cell price by a decent margin