Not really. You'd have to come up with your own standard for conveying configuration information and shutdown/restart at least (for this thin guest I'm guessing

Not really. You'd have to come up with your own standard for conveying configuration information and shutdown/restart at least (for this thin guest I'm guessing you wouldn't mind losing suspend). I believe you'd also lose memory hotplug (although I don't think you'd lose memory ballooning) unless you implemented that too. That's a new standard, and new code for your guest and hypervisor. Also I remember reading something about some hypervisors using the guest's decisions with regards to CPU power states to inform the hypervisor's setting of the same on the real hardware. I'm not sure if this is implemented in mainstream hypervisors, or if it's really useful, but that's another thing you'd lose.