I think you're missing the point. Macbook Air is simply too big. It doesn't help that it's thin and sexy as hell. The whole point with the ultra-portable-market is to make the machines small but the Air has the exact same footprint as the regular Macbook. Compared to that Sony-machine it actually have a 35% larger footprint(!) It's not about keyboard-size, screen-size or technology - heck I though Apple new!
I sincerely fear that Apple may have created their second Cube
You forgot the mac mini.