I've been using a C720 Chromebook with custom SeaBios firmware and running Linux.
While not a beast, a Haswell i3 with 4GB isn't bad at the ~$300 price point. Throw in a 128GB ssd and it's good to go. It's been my daily driver as I'm unfortunately content with 'open enough' given the market.
http://www.amazon.com/Acer-C720-3404-11-6-Inch-Chromebook-Gr... https://johnlewis.ie/custom-chromebook-firmware/faq/