What does that have to do with Xen and/or Linode? Please don't hijack threads.
As far as a Xen update -- We've got one host running Xen, with roughly 40 Linodes on it. We're no longer taking Xen beta testers.
Stability in the 3.0.2 version comes and goes, I think we're up to 16 days since the last crash. However, I haven't rebuilt Xen and the domain kernels with all the latest updates (read, from the unstable series). I'm planning on doing that soon.
The other big issue, which I knew was obviously going to arise, is how to control thrashing nodes. I solved that with UML with my token-limiter patch, however it's not that easily done under Xen. The Xen folks have mentioned a disk I/O QoS feature, but there's no timetable for it.
Suffice to say, I'm not confident enough in Xen's stability and quality to move everyone over to it, and I won't until I'm 100% confident that it's actually an improvement over UML in the areas that matter.
Regardless, all new hosts that have have gone online recently (host56 and up, and future hosts) are configured in such a way that once Xen is production ready, it will just require a host reboot to go from UML to Xen.
Resource upgrades are coming -- but I won't commit just yet as to when that will happen or how much of an upgrade it will be.
-Chris