The plan I have for the Linux box is for box to have two or more harddrives in removable racks, each drive with its own OS. Like, for an example only, Kubuntu on one, Gnome on another. Turn off the computer, pull one drive, the remaining one is boot. Or figure out which one is Master and which is Slave, and switch them out as needed.
Crossposted from http://fayanora.dreamwidth.org