I have a current model Mac Mini with a BenQ GW2765 connected via mini-displayport to displayport. I am also experiencing the blank screen problem. I did try connecting to the monitor via DVI (through the min-displayport dongle, of course), and that worked OK. I am fine with the 1080p resolution that DVI allows; however, I would prefer not to be stuck with that at all times. That's not why I bought this monitor.
It seems a lot of people are having trouble with displayport connections? Is that all. Is it possible it's a OSX -> Displayport problem?