Ok, we all know (or should know) that Microsoft's answer is a plain "NO!".
But we also know that recent hypervisors can support nested/recursive virtualization, provided the underlying CPU offers hardware virtualization; VMware's recent products (ESXi 5, Workstation 8) even support this natively, without the need for ugly hacks.
So, my question is: can Hyper-V run succesfully (i.e. allowing to actually run virtual machines) inside other hypervisors?
If yes, which ones? And how?
This is only intended for testing, of course.