Here is a great news for HTC HD2 owners that now they can install Windows Phone 7 on HD2 mobile phones. Windows Phone 7 is not officially available for HTC HD2 but DFT (Dark Forces Team) managed to develop and run Windows Phone 7 on HD2. See the video below Windows Phone 7 on HD2.
Note: do this at your own risk we are not responsible for any damage to the device.
How to Install Windows Phone 7 on HTC HD2
Finally, here is detailed video of installation procedure and Windows Phone 7 demo on HD2
You can visit DFT for more details.