wiring 2x controllers in parallel to....??

[RC-Monster Mike]

It is possible as well as pretty easy to do, but you likely won't be happy with the end result! The runtime is pretty nill when running two controllers from one pack of batteries.
I did it a couple years ago(with almost the same setup you are talking about, actually). The runtime was about 4 minutes! A better idea is to run each controller to its own set of batteries(8 cells per controller/motor will get you tons of power and a nice runtime as well).