Yeah I do this with my raspberry pi, edit with vim, for web applications the pi is plenty fast. I use the asus flip got it on sale for less than $200.
Which currently does the web fine but doesn't work for native android I have an intel machine for that stuff but for web development the pi is pretty sweet I run rails and node just fine on it with postgresql.
Well unfortunately this requires that you don't make your laptop your main development machine. I prefer to have only one machine and that machine be my laptop, though I do understand wanting desktop.
Just use a Digital Ocean droplet or something; that's what I do, and it works well. I mean, not if you want graphical UIs, but if you're good with Vim and a command line...
I spend a lot of time in places where I have no data access. I need local development capabilities. ChromeOS can do that via crouton, but data access from USB is very slow.