I did a stock reinstall of Ubuntu 12.04 shortly after getting the laptop and everything worked except for one brightness tweak which took me <5 minutes.
Dell XPS 13 Developer Edition (comes with Ubuntu pre-installed). The best part, though, is that Dell wrote a bunch of drivers for the hardware that got integrated into the main Linux kernel--I've installed over 10 distros on it (not all at once!) and on every one of them brightness, multitouch gestures, etc, worked out of the box.
Also, there's a guy who made a stupid bet regarding this: https://www.indiegogo.com/projects/typewriter-odyssey#/story