Well, I finally found the camera. It had found its way deep into the abyss of one of the home theater chairs.
So here are some pics comparing the black levels on the benq w7000 (bottom) and the hd8600 (top).
-Same feed (blu-ray, transformers 3 from ps3)
-Same screen (obviously)
-Theater is painted black (ceiling included), no ambient light
-Dynamic irises on (cinema mode 1 on HD8600)
-Manual iris on hd8600 all the way open - setting 9
-W7000 cinema picture preset
-W7000 on low lamp mode
-User picture preset on hd8600 (pre-calibration though, I had not yet done the brightness/contrast correction which improved things more)
-HD8600 on standard lamp mode (not bright)
-Canon Powershot 780is without flash (not a fancy camera by any stretch!)
-200 hours on W7000
-19 hours on HD8600
It's definitely not a perfect test (if I can even use that word in this context), so take it for what it's worth.
All in all, the HD8600 really is a fantastic projector. I'm very pleased with the image and would recommend it to anyone who likes the look of dlp and wants good black levels, and doesn't want 3d. And really, the best part of this projector isn't the deepest black it can produce, but in the in-scene contrast which gives the image so much more pop than anything I've had the pleasure of seeing (PTAE7000, W7000 from this year's models).
Gaming wise, both the w7000 and hd8600 totally meet my needs given their very acceptable input lag (for most) and excellent handling of motion. The HD8600 in particular is so responsive (even with frame interpolation on) and motion on it looks incredible. I'd be very interested in having someone do a lag test on it and would be very surprised if it doesn't have less lag than even the PTAE7000.
Anyway, hope this helps someone on the fence about either of these units. They're both awesome. I don't think you can go wrong either way.