There are a lot of rumuors about Windows running everywhere and looks like it comes true. We know Windows 8 is for PC/Tablet and it would be a surpise if its runing on the next Surface.
WP8 is going NT kernel
XBox is the next
Here my 2 cents on this topic in the conext of WPF/e (aka Silverlight). http://janhannemann.wordpress.com/2011/11/07/the-shift-from-wpfe-to-windowse/