Because at first glance it will pass for a macbook air.

I don't say that with any bitterness. I have and love my air, but as I find myself using less and less of OS X, and really just living in iTerm and my browser, the real appeal of the Air to me now is the hardware. If the Ultrabook stands up to the Air in quality, I'm seriously considering the Ultrabook + Ubuntu (double-u?) for my next notebook. Also assuming Ubuntu runs well on it, which my guess is if it doesn't now, it will soon.