i have a 1100 mah Black and decker battery that i've experimented with, and its pretty damn durable!
i've overcharged it, over discharged it, and even (accidentally) shorted it! and yet it still works. I am just running 2s1p, and it runs OK, but thats because its too much amperage for it to handle (thus votage dips). i'm sure if you hooked two up in parrallel, it would work much better.
i was thinking this battery would be good for a "spec" class, both on and off road. cant gear too much, and since its such low power, brushes dont wear as fast. Plus they come with a hard case (Roar legal?)
Cheers!