Fault Tolerance/High Availability

Hello, I work for a data center where we use a whole lot of VMware's "Fault Tolerant" Solution. As a personal project, I want to piece together an alternative solution out of open source software.

Here's my punchlist:

*Configure Ubuntu to be as slimmed down as possible so that I may call it "Just Enough OS"
*Install and configure Xen with XenMotion
*Prove that both the physical and virtual fail-overs work as intended
*Prove the automatic repair of failed virtual machines.

I've already been reading up, I'm just wondering if you guys have any links/white pages that may be of assistance.

Thanks for listening,