My next step was getting my PC hooked up to my AV system (a Denon AVR-3805 connected to a Dell 2300MP projector). I ordered a
Sewell VGA to component adaptor, which is working fairly well, with a few caveats, the main one being I've only got it working at 1024x768@75 Hz and normal windows from the PC look like crap honestly, but MythTV looks fine. This is good enough for my purposes but I don't expect to be web browsing through my home entertainment system. Supposedly the adaptor should take 1280x1024@60Hz, but I can't seem to get my PC to output @60Hz no matter what I try, including adding the following to the Monitor section of my /etc/X11/xorg.conf:
# V-freq: 60.00 Hz // h-freq: 63.73 KHz
Modeline "1280x1024" 109.62 1280 1336 1472 1720 1024 1024 1026 1062
One nice plus of the adaptor is that it comes with a cable with a built in VGA splitter so it can drive both my regular LCD monitor and my AV system.
It also comes with a remote, I guess so that if you have to mount it near a projector or some place hard to reach.
But all-in-all I'm very happy and I'm now watching MythTV on my 8-ft projection screen.
The remote is still not working the way I'd like, but that's "to be continued..."