I have a couple of temporary builds of xen release candidates available
for testing; xen-4.0.2-rc4 built for F14 at
http://koji.fedoraproject.org/koji/taskinfo?taskID=3085546
and xen-4.1.1-rc1 built for F15 at
http://koji.fedoraproject.org/koji/taskinfo?taskID=3086043
Also if you are interested in testing packages for RHEL6 see
http://koji.fedoraproject.org/koji/taskinfo?taskID=3086043
Michael Young