I haven't, unfortunately. I'm planning on doing it eventually, but it'll probably be a while. The tl;dr though is a RasPi hosting a local-only wifi network and Mosquitto + ESP8266's everywhere. I was originally going to go for Arudino+NRF24 wireless, but ESP8266 is cheaper, smaller, longer range, simpler and still compatible with the Arduino library.
Have you documented your setup anywhere?
I'm DIY-ing something similar and I'm always curious how others have approached things.