I haven't even picked up my cart yet (getting it on 4/13), but today I ordered a BatteryMINDer 48021, a MadJax Genesis Rear Seat, and a rear view mirror. I better hold off now until I get the cart paid for. ;)
By the way, I found the BatteryMINDer for $202.98 shipped from BatteryPlex. I haven't ordered from these guys before, but it was the best price I could find. So, crossing my fingers.
http://www.batteryplex.com/batteryminder.cfm/m/48021