Here's my "proof of concept" assembly. I was a little worried about the added bulk and weight, but to me at least, the controller feels a little nicer to hold because of the weight. The voltage regulator seems really good, registering 6.01 volts. And so far it seems to drive the motors with no problems. But then again, the regulator is rated for 5 amps and I already measured the draw of the two motors at less than 1 amp...so I didn't expect any problems.

So now I'm just toying around with ideas on which way to run the wires, should I get an "L" connector, etc. I'm also considering just wrapping what's there in black duck tape and calling it a day :P