First problem – The version of Xen it had was 3.1.something. The latest one is 3.4.2.
Followed the directions here to grab 3.4. (Essentially, add a repo with the 3.4 rpms built, then yum groupremove virtualization, yum groupinstall virtualization. No idea why a bunch of stuff was dependent on Xen, but it was – stuff like gnome-volume-manager, of all things. And pcmciatools or similar.)
Trying to get ubuntu 9.10 and debian setup and running. Complicated by my drive having bad sectors that were only discovered when I tried to mount the filesystem for debootstrap and ran into read errors.
DBANing a new disk to make sure that that disk is fine now though. See how it goes. *crosses fingers*