you are also aware that this is possible with Win XP and above?
ugh... there's a reason for WinRT:
http://en.wikipedia.org/wiki/Windows_Runtime
Microsoft is betting on crappy developers using javascript in combination with microsoft's COM based extensions. These extensions are written by the core Windows team in C++ so they're fast and optimized (good) but in the real world there will ALWAYS be a case where a windoows control is not enough and custom code will have to be written to implement features.
So developers are faced with two options: release a limited application with features only supported in the core windows extensions, or implement the custom features using C++ (l33t coders), C#/VB.Net (managed code posers) or
javascript (n00bz). Since C++ programmers are not exactly a dime a dozen, guess who the average metro style developer will be? Most likely also metrosexual.
do your homework!