This project has been a godsent! The latest Daikin indoor units have a built-in WiFi module which only allows control through their cloud infrastructure. Besides it being a privacy and/or security issue, it's very slow and buggy (e.g. I've had two units reset their credentials after a power outage).

There are two caveats to going the Faikin way: you need to source or build your own cable that's compatible with your unit, and there's no access control (that I could find) for the web interface so you need to firewall and proxy it properly.