Well, I bypassed the receiver, and the picture doesn't really look any different. My setup is my living room, and though I have black out curtains I was trying to calibrate in what I considered pretty much "typical" lighting conditions this afternoon. Now that its night, and pretty much pitch black in my living room, when I run the disk I think maybe I can almost sorta make out the ideal star for the brightness pattern, but I don't know if its in my head or if I'm actually seeing it (no matter how high I turn up the brightness). I still can't see the ideal star for the contrast pattern.
I still haven't ruled out the possibility that clipping could be due to the graphics card settings, but the WOW manual does state that I can expect "'white clipping' behavior in...projectors with modest light output expectations", and though this is my second bulb in less than 2 years, maybe that's the issue.