Earlier quoted context omitted.
You seem to have only looked at the older PCs. Have you looked at the Dell XPS 13 or Microsoft Surface Book? They may dispel your complaints. You can even buy the XPS with Ubuntu.
Worthless battery life for such costly machines. I would've bought the XPS 13 with Ubuntu otherwise. Edit: I read reviews like this http://www.iretron.com/blog/posts/dell-xps-13-is-a-major-dis... cannot find the other ones though. It is better than I remember; I thought it was worse. Still; 6 hours is not really usable in my book.
http://www.trustedreviews.com/dell-xps-13-2015-review-batter...
which gives a rated battery life of 18 hours and a real-world use battery life of 9-10 hours
http://www.laptopmag.com/articles/dell-xps-13-battery-life-f...
This article suggests a battery life of 12 hours.
What kind of battery life are you expecting?