okay I can report 100% success on my first try
i installed the 120 gig into a windows pc and got the hard drive key from my xbox evox backup eeprom.bin, and liveinfo
I booted into gentoox on my xbox, and use a command like this (syntax may not be 100%)
dd if=/dev/hda | ssh 192.168.0.199 cat -> /home/xbox.raw
this piped the dd output thru SSH onto a pc running gentoo with the 120 gig drive installed into it
then i did a cat /home/xbox.raw > /dev/hdb (the 120 gig) and it dumped the hard image to the 120
i then booted that pc with a dos boot disk (actually a dos boot cd) and ran unlockx, locked it with my key, rebooted, verified it was locked. installed the drive in my xbox and it worked like a charm. PBL and evox loaded, I formated F: with evox and now I'm transferring gigs of fun stuff to my new drive!
this method is much easier and safer in my opinion, as you never have to take the xbox original drive out of the case until you are ready for the end result swap, never have to mess with locking or unlocking it or hot swapping