Then there's a radical alternative: Perhaps Microsoft simply needs to go all-in with its Metro interface and ditch the windowed style of computing entirely.
Windows 8 already shares more than a few similarities with a concept design called 10/GUI, which designer R. Clayton Miller conceived as a way to bring a touch-style computing experience to the desktop. It's got navigational nuances that lend themselves to on-screen touch much better than the non-Metro interface in Windows 8.
Miller's 10-minute manifesto video sums up his concept far more effectively than words can, but its most powerful idea hinges on the abolishment of freestanding windows and the adoption an oversized, multitouch trackpad that correlates any touch to the same relative position on the screen.
That kind of radical re-conception could scare customers.
Microsoft is still wading in the shallow end with Windows 8, though, and its Surface struggles make one thing very clear: there is no true hybrid on the horizon. Any expectation that one slab of hardware can fully replace your tablet and your PC is both unrealistic and futile.