But we already pretty much have that (or will have). It's a surface pro or any other i386 tablet/touchscreen laptop.
Well, I agree on this to a point.
But such mode would still have some benefits.
For example, you're fine with the ARM version but you need this one Win32 program and no chance for a port to WinRT exists, because of complexity. But the devs can "easily" re-compile it.. Lots of custom software in businesses could be used this way with cheaper pad-like devices too.
But anyway, the whole ARM affair is mostly a side-issue for me, since I have no interest in it in any form. My primary issue with the ARM version (aside from the WinRT limitations) is for the most part the terrible "Windows RT" name.