Xen 3.0 on Debian

We are using Xen 3.0.1 on Debian Sarge from several months. Working great. Finally on HowtoForge they upgraded their manual too - The Perfect Xen 3.0 Setup For Debian. Good. Also something else bring my attention: Setting Up A Highly Available NFS Server. We need this for live migrations - Xen need to get the OS filesystem image from the NFS, but it becoming a single point of failure.
Like a long time shot Parallax (cluster storage system under development by the Xen team with COW and snapshot features) seems pretty atractive.