Pinetab Smart Home expansion board?

[pfeerick]

But then the downside would be that the tablet would have to stay fixed to that stand for the radio modules to be connected. If there was a built-in module, it could stay mobile and control the home at the same time.

Maybe use something like an ESP32 in the base as an access point, have the PineTab auto-configure to use it when it's docked (i.e. no user configuration required). Then the PineTab can connect to it when it detects that it is removed from the dock. Therefore you get the best of both worlds - essentially 'hard-wired' when docked, or wireless when it's not docked.