Why not by a Chromebook Pixel (2015)? Seriously.
I think if Google decided to sell the Chromebook Pixel (2015) with Linux instead of ChromeOS, OP, I, and a horde of other developers would all buy it.
In reality, it doesn't seem very easy to install Linux on the 2015 Pixel or any other Chromebook without either remembering to press Ctrl+D on each boot or by going through a significant set of hoops.
I want the Pixel for its USB C charging capabilities. the biggest reason I don't get one is because while I have no regrets with wiping windows, I have FOMO about wiping ChromeOS.
if the SSD weren't only 64GB... I could put Debian and chrome OS on it.
Have a look at https://github.com/dnschneid/crouton
It lets me run ChromeOS most of the time, and then fire up an Ubuntu session when needed.