I see a lot of like-minded folks on this thread, and I can confirm a few things:
The Zenbook Prime is a sexy, fast and handy machine. The screen is excellent, and visible easily even outside on the balcony in bright sunlight. The keyboard is good, backlighting, etc. Sound is nicely tonal, and doesn't screech in either direction for normal volumes.
I bought the UX31A with i7 processor, 4Gb Ram. My unit runs Linux Mint 13, with the cinnamon interface, in case that matters. It's a wrapper around the Ubuntu 12.04 release. Before I shell out the 1000+ euros, I took a ubuntu liveboot usb to the store and confirmed that most things work -- and the same things do not work as listed in this wiki I have updated some entries in that wiki to reflect this.
Using the fix, most function keys do work. The touchpad usage is bearable, until a proper fix comes our way.
However, a serious problem in such a machine is the poor battery life. After 100% charge on the battery, with the brightness set at 50%, I unplug the charger and the immediate number is 3 hours battery remaining. That is hardly acceptable.
I have tried the Power Optimization tricks listed in the wiki above, and also enabled ALPM. My first tests were hardly promising: I've added an entry for wiki here.
Looking for suggestions on what to try to improve the abysmal battery performance.