OK, I decided to go ahead and risk my phone and try it out. I cleaned out the radio image and a few other things that made me nervous, edited the updater-script and build prop, resigned everthing. I did a nandroid backup of course, did a full wipe, installed the modified Sprint Gingerbread zip, flashed gapps, then flashed mmarz's sprint-to-ov zip file.
The phone started up, showed the standard LG logo, then all of a sudden there was an explosion and the sprint logo appeared, kinda cool actually. It then went through the standard android bootanimation, and next thing you know I'm at the account sign in screen.
I hadn't taken the necessary steps to get it working with the virgin mobile network, and the wifi modules don't seem compatible as is, but I was able to boot into the OS, and use the phone minus network/phone capabilities. The interface is buttery smooth, and everything else seems to work great.
Good news for future ROM upgrades and builds!
Edit: Power off just hung at the powering off box, pulled battery, rebooted, wifi works fine, signed into market fine. On second time I opened market, it upgraded.