I think they really need to adopt how MS does the charm menu or whatever it's called. Swipe in from the edge to show the buttons. Of course the problem with that is you now require two actions just to press home.
I really think this is going to become a standard interaction on touch devices. It sounds like it would be the perfect solution in this case.
Then again, Google have been trying to avoid the concept of hidden menus. Misguided IMO.