Just an update:
I lowered contrast from 50 to 42 and now I get zero "flashing" in the areas I previously did (except the dead pixel test, but that causes all manner of screwiness on other LCDs in my house I've tested and is not unique to the BenQ). Any amount of scrolling/zooming in browser/Google Earth on light backgrounds works fine now with no dithering/crosshatching or flashing.
I've got until January under the "Iron Egg" guarantee from Newegg so I'll keep the monitor for at least another week and tinker with it to see if I can find anything wrong with it.
So far:
Pros:
Good color reproduction and excellent contrast
Better response time and less screen tear than my previous panel
Very immersive experience gaming
I love the screen real estate for desktop use
Cons:
Some uneven panel uniformity/banding - not really a huge deal, but it's there if you look for it
A little bit of black "crush"
The "flashing" issue which I've worked around for now, but which is still in the back of my mind. I'll be trying to reproduce it in games like Skyrim or other "third person" view games (so far no luck there, which is reassuring)
I was trying different settings for contrast/brightness... sadly that didn't solve the flashing problem.
In skyrim you can test it anywhere outside during the daytime. first/third person had flashing for me. also in some interiors..