Loaded Cleardroid 1.1 (basically stock GB ROM) and it loaded! Immediately made a backup in 4ext recovery as a "baseline", as this proves my theory...there had to be SOMETHING, some file, that was screwing things up.
The behavior worried me at first - it went to the white HTC screen, stayed there for 2+ minutes, then went to the black HTC Quietly Brilliant screen and stayed there for 6-7 minutes before I battery pulled, did another format all except sdcard in 4ext, reloaded the same ROM, and rebooted. This time, I waited for the black screen to come up, then connected it to my PC and ran the Android SDK ddms.bat to see what was going on...and much to my surprise there were a LOT of errors and warnings, but the system processes kept kicking on one-by-one until I got the Sense lockscreen.
I've created a backup of this working rooted (mostly) stock ROM as a baseline in case this happens again - it's worth the loss of SD card real-estate to know that I can re-initialize everything.
Now that it's breathing again, let's see if I can get my original goal to work...a Collective ROM loaded properly! Updates incoming....