Is the not wanting an arduino in every device due to cost, size, power consumption or something else?
Almost every gadget you use today has some sort of microcontroller in it. It's just so small that you don't know it's even there.
I pretty sure something like the xbee (expensive) can function standalone to transmit the status of switch inputs. Perhaps the nRF24L01+ has something similar?
Are these things battery powered? Who has the job of changing, or charging a 100 batteries?
Anything that is portable will get stolen. if it's tethered then why not use a wired connection for data and power?