On the "little machine for custom jobs" front, can anyone suggest a low cost subnotebook, x86-64 or ARM (i.e. Chromebooks OK) where I can wipe the Google software and install some version of Ubuntu? I've been using EeePC Seashell machines for that for years, but they're wearing out and I need something close to current production.
I'm looking for a machine where there's not too much difficulty doing this. That varies with the machine. Some require removing a jumper to let you overwrite the OS. Some require overwriting flash memory with somewhat sketchy binaries.