All we need is for Apple to do what Samsung and Microsft are already doing and make their tablets chock full of RAM and storage and make them easy to add a keyboard and mouse to, as well as a docking station or at least video port so you can go out to a full size monitor when needed. Best of both worlds. Crazy portability and full desktop functionality (if not speed) when stationary.
Thats a laptop, and the portability wont be crazy once you add all that stuff, probably the new 12" MBA be smaller, or similar, and far more functional