There are instructions and some fuzzy pictures of the process in my forsale thread for the boards here:
http://www.hpcfactor.com/forums/forums/thread-view.asp?tid=3018&start=1
If you need help with installing the board, contact me when it arrives.
You may or may not be able to restore a backup of your 720 rom contents once you upgrade to the 728 board. I was able to restore a backup on mine, but the keyboard would not work! Doing a hard-reset wasn't really an issue for me. I install almost everything onto a CF card, so all I had to reinstall were the drivers for my CF WiFi card and Bluetooth. I keep the .cab installers for both on my CF card
(marked read only so they can't be deleted!
), so hard-resetting isn't much of a loss for me.