But why stop there? (Score 1)

Microsoft has already shown they are the kings of user interfaces and windows slickness. They could not only build office applications that run on windows they could completely overtake the windows side of linux. Its no sweat for microsoft to abandon their shoddy kernel, no one cares about it anyway, people just want a familiar bunch of windows to click on and their application to work. By doing realtively little microsoft can open up an entire new market using their competition as another medium to plug their product. KDE and Gnome are the only real competition that windows has and for a relatively cheap price microsoft could sell just the windows enviroment that would be running on a stable, secure linux kernel and charge enough to make it worth it for them and their customers. Whats more with the size of the company and the amount of developers that they have to throw at the open source code they could have major implications towards the general direction that it goes. Just think in the future you could find yourself running a windows for linux hybrid envoriment and playing games on a directX for linux port!