After going through several Linux laptops over the past decade, including a couple of Thinkpads, I agree. My current Chromebook running Ubuntu is by far my favorite.
The whole setup comes in under $300: buy a certified refurbished Acer C720 from Acer with 4GB RAM and 16GB SSD (http://www.amazon.com/gp/product/B00L87JC80) and, separately, a 128GB MyDigitalSSD (http://www.amazon.com/gp/product/B00EZ2E8NO). Replace the SSD and install this custom-made Ubuntu distro that includes all of the fixes for the C720: https://www.distroshare.com/distros/get/12/. And that's it!