I've had a few emails asking about Xen 4.2.0. I've got a test version running and am monitoring it over the next few days. If it proves ok, I'll push it to the repo.
In the meantime, yesterday I pushed a new kernel-xen package (3.5.4-2) which has the option for HPSA raid adapters enabled. This was an oversight originally and should mean that the kernel will boot properly on HP servers with this type of RAID card.