I came across this video that's showing what appears to be an HTC HD7 running Windows Mobile. It seems to be an emulator of some kind which runs Windows Mobile 6.1 on top of Windows Phone 7. In the video, they (team DFT), claim to even be working on Wm 6.5 version!! It currently looks to be using virtual buttons to imitate hardware buttons. Check it out..
http://www.youtube.com/watch?v=1FNls9Hi6TQ