http://blogs.technet.com/b/hugofe/archive/2010/06/16/windows-2008-2008-r2-hyper-v-amp-failover-clustering-better-together.aspxWINDOWS 2008 / 2008 R2, HYPER-V & FAILOVER CLUSTERING Better Together. Updated cluster limits for Hyper-V R2. Until May 2010, the support limit was 64 VMs per host and up to 16 nodes in a cluster with one node for failover (a 15+1 cluster) for a totalen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)