I'm considering getting the Pixel and running Linux on it, but am extremely annoyed by the lack of upgradable storage.

The $250 Samsung ARM Chromebook has USB3 (~100MB/s) and a fast (~50MB/s) SD card controller. The $1300 Pixel only has USB2 and a slow (USB2) SD card controller and no real PCIe slots, which means that you can never get more than ~17MB/s when trying to increase the tiny internal storage.

Honestly, the $250 ARM Chromebook is among the very best things you could do for development (in my opinion). I can use ChromeOS for when I'm not doing anything hardcore and then just open a chroot jail (via crouton https://github.com/dnschneid/crouton) with a full xubuntu/xmonad install when I really want to get cracking. Both open so quickly it's almost disorienting, either from start or from sleep. It's the same size and weight as a Macbook Air and the battery life is outstanding (I've come quite close to the 9 hr mark when I'm not listening to music on speakers). The only downside, at least for the purposes of this question, is that it isn't fully HD, or rather isn't 1080p which is what I assume the OP meant. Still, I'd say that this is by far the best computing investment I've ever made, and I'm happier with this than I am with the $1000 laptop I got 6 months ago.