@Frank T:
"Even if mixing vmotion and DAG technically works, their point seems to be "Combining these solutions adds complexity and cost, without adding additional high availability."
The cost and complexity are the licenses required for vmotion and the work to configure it. This work may be trivial if you are already running a vmware environment that uses vmotion for other things but if you are learning it just for Exchange... why."
That's not for Microsoft to decide, IMHO, and it's symptomatic of an arrogance that seems rampant. The ONLY valid reason for Microsoft not to support something is if it doesn't work or is unreliable. To not support a feature implementation because of cost is like saying that they won't support Intel processors because AMD processors are cheaper and sufficient for the workload.
This is a thinly veiled attempt to remove value from a cloud model (server virtualization) that the Exchange team doesn't approve of.