Apparently I was giving the Mac enough time to boot. I let it sit at the grey screen with the Apple logo and it eventually booted up.
Since I already burned rEFIt onto CD, I had the installer read to go. I double-clicked "rEFIt.mpkg" and it went through the installer as usual. If I knew the root password, I could tell you if it worked properly, but it looks like it will
Code:
Automatic Installation with the Installer Package
Both disk image distributions (.dmg and .cdr) also contain the new installer package. It will install rEFIt on your Mac OS X installation volume and make sure it is active. This is now the recommended way to install and use rEFIt.
The steps to install rEFIt this way are as follows:
1. Download and mount the rEFIt-0.9.dmg disk image.
2. Double-click on the “rEFIt.mpkg” package.
3. Follow the instructions and select your Mac OS X installation volume as the destination volume for the install.
If everything went well, you’ll see the rEFIt boot menu on the next restart.
THUS, the problem I has originally was that the boot partition was flagged "hidden" and the Mac HFS+ partition was flagged "hidden" and "lvm". Once that was changed, the Mac was able to boot, and rEFIt was able to install.
Thanks again to everyone that helped, and an applause to the rEFIt developers as it's an excellent program (very clean aesthetically too).