I recently had success installing ChrUbuntu on a $199 Acer Chromebook and it works great with Armory. I think this is the cheapest offline laptop solution at the moment, but if someone has a better one, please let me know!
Glad to hear it, although one should note that the Chromebook you're referencing has an x86-64 processor. That's why you had no problems installing Armory.
