New MacBook Air Using Scaled-Down Thunderbolt Chip

[drsmithy]

They'd then have a total of three displays [...]

The Intel HD graphics in the Air does indeed have dual monitor support.

However, what you are proposing is one internal display + two external monitors = three displays.

I would vastly prefer two external screens and the internal screen disabled, to a single external + the internal.

In the latter scenario I am always welded to the tidgy internal screen. In the former I can hook up a couple of 27"s if I want to, for much more [usable] screen space.