How about a pair of these: proteck lipos? In my opinion 12c at 5000mah is too low. Those vxl systems can easily pull 100amps, even on 3s lipo. And the maxx truck will load those motors, even with two of them.
I saw those to, but I don't think they'll fit. My Maxamps battery is 26mms tall and it's close to the motor mount. It looks like 30mms will be an extremely tight fit.