FYI: I'm on HBOOT 0.83.001 (a Telus Desire). I used v3.1 of Unrevoked, and I got the image file from a link on a page, of the Droid Den guide on rooting. At the time (ie. a few hours ago...) I didn't know no nuthin' about version numbers and their differences, or the importance of getting the latest.
HOWEVER, all that is copacetic because I just fixed the problem. Turned on SYNC via HTC Sync, and then ROM Manager allowed me to both flash the latest 2.507 recovery image, and partition the SD card. Hope this helps anyone having the same problem. (I know the wipe worked, but I've yet to confirm the partition worked. As it says I have 6.92GB free, but its the 8gb card that came with the Desire, and I specified a 512mb partition. ROM Manager does not specify wether its EXT2 or EXT3, but LeeDroid himself recommended using RM for the format, so....).
After two FULL days of intense research on ROMS, RUU's, rooting, hacking and hair-tearing and frozen HTC screens and whatnot.... I think I'm finally ready for step 4: Installing LeeDroid 2.2a! (I thought that would be my biggest problem. I expect that to go like clockwork).