After looking at the various projector mounts, I decided to go with a flat-screen TV mount instead. All of the less expensive mounts I could find looked flimsy, where as the TV mounts for the same price were sturdy. Also, I wanted to mount the projector behind the beam as shown.
To get this to work, all I needed to do was drill two holes in the universal mounting plate. It would be nice if projectors and TV's had the same standard bolt-pattern for mounting...
This configuration allows the projector to sit behind the beam, and just under it (keeps the headroom). Another benefit is that the projector sits pretty much out in space, so the it gets maximum air circulation around it. We had the projector sitting on a table for a while, and the secondary fan came on all the time. It doesn't here.
I also mounted the UPS on the beam to keep things simple.
After having this set up for a day, I immediately noticed that a very faint 60Hz line (slowly rolled up the screen - you had to be looking for it) disappeared from the image. The power condtioning function of the UPS is obviously cleaning up the "dirty power". This alone makes it worth the $50.