@ zim2dive regarding backup strategy.

I believe you have to install chameleon separately, thats what I had to do.

I was in that situation you described with the 10.6.3 update. I had made a backup before trying the update, (with superduper, it has a 'smartupdate' option to only copy new files, its quicker). When the update failed, I simply booted from the bckup drive and used superduper 'in reverese', to get back to 10.6.2.

The way I see it, the advantage with having the bootloader installed on the backupdrive is that you can just switch drives and be up and running. Which is handy if theres a mechanical fault on the original drive or you can't find that usb stick you had the bootloader on. I have a setup with the drive outside the case so its easy to switch drives, but I have a very quiet 500gb single platter drive, it might get noisy if you have a 1TB drive.