I would love to see someone sell these as preconfigured as minimal bandwidth tor exit nodes with wifi so they can be spread far and wide. Just connect to power, make sure it is connected to a wifi network and then leave it alone. Just make sure it advertises itself as such so that law enforcement knows that it is likely not owned by the owner of the Internet connection and therefore doesn't make sense to do anything other than find the device and disable it if that's what they want. It should have a similar disclaimer as the standard tor exit not notice, except it should say something like "this tor exit node is operating on a disposable computer and was placed clandestinely on this network without the consent of the owner" or something to that effect.
I know there are ethical implications here, but that doesn't mean that something like this shouldn't or won't exist eventually.