This doesn't answer your question but I thought I would weight in regarding your opposition to buying the Macbook Air. I bought a 13" Air when the latest revision came out and it's by far the best laptop I've ever used. Even though I use OSX on it most of the time, because it suits my work, the form factor is what sold me on the device. I wouldn't hesitate to buy one to run Linux or even Windows full time on it. My only concern would be the trackpad behavior, but the machine is so good I'd write my own driver for Linux if I had to.
Apple does a fantastic job of putting hardware of moderate specs in a better package than others. The device just feels better in your hands. It's almost intangible but no matter what OS you're using its a joy to use. Perhaps you don't feel the same way, but I think its worth keeping an open mind, especially if money is not an object.
This post probably comes off as yet another fan boy, but I hope it doesn't. A few years ago I wouldn't even consider Apple, but I finally had enough of the cheap plastic crap that vendors insist on shoving down our throats.