It's going to take a big connector to fit 6 of anything larger than say ~18ga. Unfortunately the Amphenol C16-M connectors that I used on Monkey's beta22 are only rated for 250V so I'm not sure they'd work. If push comes to shove just go DUAL MONOS on its ass and do two 3-wire cables. That has to be like, at least twice as good, right?
As far as the cable goes I'd just braid your own.