I'll put my .02 in on this, I have done a project right in this neighborhood. I have an associated RC10GT, that i converted to electric. I built it for hi-V low mah battery packs, I would say its a sucess. I can run 40 minutes on 18.5v 2500 flightpower pack, Geared at about 35mph. The setup is a quark 80 esc/lehner basic 1200xl, the forementioned 5s 2500 lipo (Flightpower25c). Power wise, it could flip, If i tightened the slipper. Gearing wise i have it set at 20/66 with 32Pgears. I can run it for 45 minutes and nothing is hot, Barely above ambient. I have run this in all seasons ( real hot this last year in GA) and no problems. I wouldn't have no trouble running with any 2s setup, power, speed or runtime. It only pulls 40 amps peak, I could have saved a bit of money and got a quark 65 if i knew that. The thought has crossed my mind to try a 33 amp quark or mamba 25 on this truck, just haven't got around to it.
Below is a couple pics of my setup, I got eagletree on it, but not at my computer at this time. Will try to get them up later