So, I have not tried everything people have suggested, but I've gone through most stuff. Next up is trying individual components, but I didn't get there tonight. I do have a couple updates, though...

- I caught the error on the BSOD before the box restarted: some about not successfully recovering from a driver crash. It seems that when I do something crazy like run an ATI WU, it crashes the driver (both 10.10 and 11.2).
- Interestingly, when I'm in CCC with stock settings, and hit the "Test Custom Clocks" button, the clocks fail. With stock settings. Ugh.

I did switch cards around, and things work the same no matter which card is in the first slot. I'm beginning to think this is a PSU issue (though that is little more than a blind guess at this stage). This is a bit disappointing, since I have this PSU, which is supposed to be good.

Other thoughts/suggestions before I begin to cry myself to sleep?