This is a great build, Drew. I'm glad to see these 3220-based systems finally getting some more testing done. I've been too busy with BMS-related stuff to even ride any of my bikes for months now, but that is going to change soon.
I'm curious on what you used for your D-Y switch, do you have any shots of this? Where did you get the switch? Any idea why the first one failed? A simple switch is still a ton easier than using a big pile of relays.
The one thing about these setups that hasn't been solved yet is the lack of "stealthiness". It's a little hard to sneak up on the Lycra-clad 20-somethings with a setup that sounds like a Singer sewing machine on steroids.
Offroad, though, it doesn't really matter, I guess. Do you get a sense where most of the noise is coming from? The #219 chain/drive sprocket, would be my guess. I'm wondering if a belt drive, like Kim/AJ and Matt P. are using, would make these setups any quieter. Once Kim gets his cruiser back up and running, and maybe does some videos with his camera stapled to his head, we'll see if there's much difference. I think the 3220s b\y themselves are a bit quieter than the big Turnigy outrunners, and that coupled with a belt-drive 1st stage, like you have, might reduce the noise factor.
The motor and 1st stage usually just make a sound like a jet turbine winding up (sounds just like an F101 engine starting up on an F16...), which I think sounds great. Getting rid of, or reducing the 2nd stage racket, is the real challenge.
Anyway, this is great, and I look forward to seeing your progress.
I'm also looking forward to seeing how D does with the SRAM DD setup. My gut still says this will be okay, and that in 2nd, where the ratio is 1:1, it shouldn't be any different than a straight hub. Even in 1st, I think it will be okay, because there's too much torque available to keep your ass on the bike, so you have to either start pedaling first, or ease into the power. I think the reason that Kim's unit failed so quickly is that his setup is bigger/heavier, with a long wheelbase, so less prone to throw his "generous" backside off the back end.
A lot more of the torque is getting to the wheel.