Like the idea. However, wouldn't that be a wasted resource? I mean windows, eh. Just me though. Back almost 20 years ago, there was this program litestep, changes windows kernel.
You could take the open source code from them, and create a dev wet dream.
Basically using that code you'd be looking at changing the windows environment. Which in its own way can be useful.
I like the vision though, hopefully you're still chasing it.
Where I said kernel replace that with shell, believe that I recalled incorrectly.