Hyper-V on Windows 7?

I would say it isn't possible to use Hyper-V on Windows 7. You could put Server 2008 with Hyper-V as the host and use Windows 7 as a guest machine. Your best bet is to either use the new Windows Virtual PC or VirtualBox and the like.

Windows 7 is a client OS and thus does not support the bare metal (level 1) Hyper Visor technology that Win2k8 server does. However Windows 7 does have a new Virtual PC client - which is NOT the same as the old one (which used emulation), this basically uses a level 2 hyper visor. Mark Wilson covers it in detail in his blog post

So it is much faster than the old one, but not as fast as native Hyper-V. The trade off is that with this you get more hardware support (USB devices are fully supported) and some of nicer features like drag/drop support.

Finally an important note (since you already have VM) is that Hyper-V machines do not natively run on the new virtual PC due to HAL issues (I have yet to try uninstalling the Hyper-V components first, but I suspect it won't work because the HAL is a driver update). Old Virtual PC to new Virtual PC is fine.

Hyper-V only available on Windows Server 2008 with Hyper-V or the freely available Hyper-V Server

You could install one of these as the base OS and then install Win7 into a Hyper-V VM

In fact, yes, it is somehow possible.

Windows 7 includes a "boot to VHD" feature. So, it is possible to install Windows Server 2008 R2 (64bits) inside a VHD that resides on the Windows 7 file system. This system will be available as dual-boot on system startup.

When booted on Windows Server 2008 R2, it is possible to enable the Hyper-V Server Role and everything works perfectly.

In order to set this up on your Windows 7 workstation: a) Boot on the Windows Server 2008 R2 Installation Media b) When the language selection dialog appears, hit Shift+F10 c) In the command prompt, run a series of command to create a virtual hard disk.

Something like:

http://technet.microsoft.com/en-us/library/dd744338(WS.10).aspx

diskpart create vdisk file=c:\windows7.vhd maximum=25600 type=fixed select vdisk file=c:\windows7.vhd attach vdisk

Then, you can proceed with the installation.

Windows 7 has a new version of Virtual PC available currently in Beta. This is available here. There is also the new Virtual Windows XP Mode for Windows 7 available.

Has nobody considered creating a Virtual Windows Server 2008 R2 instance on a 2k8 box, and booting to that Hyper-V virtual hard drive using Windows 7 multi-boot? Win2k8R2 and Win7 can both boot to a Hyper-V OR Virtual PC virtual hard drive so that the virtual host becomes the physical host.

As an added benefit, the virtual OS running as a physical OS (multi-booted to Win2k8 R2 virtual hard drive) should be able to utilize the virtualization hardware to run Hyper-V. With the assistance of a 2k8 Hyper-V box, you won't even need a separate partition to do this.

I recommend researching "boot to a VHD with Windows 7." As stated above, this solution would require another Windows Server 2008 box, or a Server 2008 multi-boot partition to create the VHD (I have a spare / clean external hard-drive for such drop-of-the-hat configurations). This VHD, once created, should be movable to a Hyper-V server, and if multi-booted in Win7 should be able to utilize the virtualization hardware once the HAL is detected.

Someone smarter than me should chime in to validate this.

You'd need to run the server version of Windows 7, AKA Server 2008 R2 or whatever it ends up being called.

Might want to look at remote server administration tools for Windows 7 (KB958830)

Microsoft KB958830