Sort of on topic regarding running Windows 8 in a windowed VM and some other thoughts about using Windows 8...
I am running Windows Server 8 beta and Windows 8 Consumer on ESX vm's, accessed through a Windows 7 desktop. I have found that running 8 in a window just doesn't cut it. The Windows key is essential to the experience. Accessing Metro from the desktop using a mouse is lame. In order to set Win8 focus on the Windows key (essentially the home key that we see on tablets) you need to put Windows 8 in full screen, which isn't too big of a deal I guess. The Windows key by itself will always take you to your app shortcuts in the Metro menu (both metro apps and classic windows apps). If you don't have it in full screen, the Windows key is focused on the physical system. Maybe I am doing something wrong in VM window mode?
Microsoft has extended the Windows key shortcuts to access various Metro menus. I just randomly hit Windows+letter combos on the keyboard while in Metro to see what they do, if anything. The desktop Windows key combos are still there as well. Server 8 also has Metro "start menu", but Metro version apps are not installed.
Seems obvious that Microsoft is trying to break admins away from administrating Server from its desktop. They want admins to install their tools (particularly the new Server Manager) on Windows 8 desktop and remotely administrate. With the exception of Remote Desktop Services, I won't be surprised if Microsoft makes initiative to push admins away from the desktop version of Server in place of Core edition with cmd and PowerShell shells. IMO Core editions of Windows 2008 isn't quite there when it comes to initial setup, particularly network. Hopefully Microsoft has extended PowerShell commands in Windows Server 8 to configure advanced networking. To me, that will make Core any easy transition. I tried going core on our 2008 R2 HyperV cluster, but with five NIC's to configure, I just found it easier to put the desktop on rather than diving through netsh to setup all of those networks. Maybe I just need a little more patience.