I have a traxxas villain (the 7.2V one) and I probably shouldn't even be considering this because of how hot the motors are after a run, but if I wanted to have even longer run times, how would I connect two separate 6 cell packs in parallel for more capacity? The ESC has a single battery input, so I would have to make a plug adapter from the batteries to the ESC. Would I just make a wiring harness like on the SV except reversed (two plugs from the batteries to one plug to the ESC) or how would I go about that?

Here ya go, this'll answer your question:

http://www.offshoreelectrics.com/inf...g-batterie.php

thanks very much