Just a FYI, but I called Happ yesterday to try to order a 49-6157-VP2, and the gentlemen informed me that they are no longer stocking this monitor and have indeed switched over to the 49-3149-VP2. The 49-3149-VP2 is still 27" (not 29, like I mentioned below) and the only difference between it and the '6157' is that the '3149' is a flat-screen model instead of a 'traditional' CRT.
I also noted that they are no longer selling the matching bezel for the 6157 and now only carry a 'flat-sceen' bezel that matches the 3149. BTW - the 3149 is currently on special, so with me beginning the building of my own cabinet, I ordered the 3149.
Anyways - to your original question - dabone's advice is good. I think that the Vision Pro will only run at 640x480 or 800x600, and both at 60hz. You could also boot into safe mode and re-select your driver to be a standard VGA card (Microsoft supplies a 'house' driver) and that would guarantee you a clean boot up.