Its always sad when you have to reduce scope for a product release. Today we revieled that quite a few of the features in the "Viridian" Hypervisor product will not make the initial version. Features such as live migration, hot-add resources such as storage, networking, memory and processor are dropped and support for processors will be limited to 16 cores or logical processors.
On the positive side, wise decisions were made a long time ago to make sure that the Viridian work was in a separate tree to Longhorn Server, ensuring it does not have an impact on that release.
For those who do not know what "Viridian" is, its a thin software layer between the hardware and Windows Server Longhorn operating system, and allows multiple operating systems to run unmodified on a host computer at the same time.
For more information on this, I point you to Mike Neil's blog http://blogs.technet.com/windowsserver/archive/2007/05/10/viridian-features-update-beta-planned-for-longhorn-rtm.aspx
Looks like he has read the mythical man-month too.