I was interested in running Fedora Core 12 amd64 as dom0. Since the default kernel has no dom0 support, I wanted to use the myoung dom0 kernels. Unfortunately, they won't work with Xen 3.4.2 which is the latest included build in Fedora Core 12 and even Rawhide. I took the latest 3.4.3 build, rolled them into RPMs, and installed it.