Another company to look at for controller- Curtis Instruments:
http://curtisinstruments.com/index.cfm? ... y&catID=10I just got off the phone with a sales/tech person, and they assured me that their 75 amp module absolutely CAN deliver 75 amps to both motors at once, which should provide solid competition to the Dynamic DX range as well as P&G. He also claimed that he thought their acceleration ramps could be set as short as 0.1 seconds, better than Dynamic and better than P&G gear will do with what they'll sell you. From what I've read so far, their OEM PC programmer is common to the powerchairs, golf carts, and electric vehicle parts. This means you would be able to buy it from a golf cart or EV conversion place without much hassle.
I don't know about the powerchair efficiencies or voltages, but I saw that they have some 200+ amp single channel controls that are rated for higher voltages. The prices I've seen (ebay, etc) look very competitive. I see some 36 volt 400 amp controllers available for $150 each:
http://shop.ebay.com/?_from=R40&_trksid ... CategoriesThey're intended for EV use, so I trust their failure modes, vibration resistance, durability, etc, a bit more than I trust the robot combat stuff. If you like massive overkill, this is the way to go. The only catch is that you need to manage processing of the joystick signal to two properly conditioned outputs.