After exchanging some e-mails with Shane DeSeranno, it was determined that the IR-pen I made using parts from Radio Shack was simply not strong enough to be seen by the Wii-mote's camera through the surface of the table. I wound up getting a MUCH stronger IR-pen off of ebay and it works great! The new pen is 5v versus the 1.2v of the LED I was using and uses three watch batteries versus the single 'N'-cell battery I had.
I also tried using shorter table legs - going from 14" to 8" - in an attempt to make the surface viewable while sitting on the couch. While this may have improved tracking for the Wii-mote, the bulky, 8-yr old Proxima projector looks really blurry. I'm going to have to keep the 14" legs at least until I get a newer/better projector that can throw an image with a shorter minimal distance (assuming it's even possible). Of course, the shorter the table, the small the projected area (regardless of resolution), so it's a trade off.
In other news, the LCD screen on my Cannon Powershot A630 is beyond my ability to repair. It still works as a camera, but I have no way of accessing the menus or reviewing images. The problem actually lies the wires leading up to the screen, and not the screen itself - one of tiny wires got pulled out of a connector that plugs into the screen. If anyone knows how to repair this, I'm happy to get some instruction.