I did a lot of shopping around about a month or two ago. There were only three serious contenders. Asus UX32VD, Sony Vaio Z 15 and Thinkpad X1 Carbon.
Out of this bunch, Thinkpad was out because of insane price in EU and because Asus had a better screen and massivelly better value. Sony didn't qualify because it felt cheap and I really dislike Sony as a company. So I the only real worthy computer was Asus UX32VD.
Running Ubuntu 12.10 I am super happy with it (although shame on Nvidia for not supporting Optimus on Linux). If I were buying a computer now, I would probably buy Asus U500 (15.4" and Quad Core CPU).
But I am still in market for a new Thinkpad, when Lenovo comes to its senses and releases something 14" with 1080 or 1200 resolution and Quad core CPU.
I have a feeling that next year the laptop market for developers will be awesome.