So my plan is to release OpenGarage first (ESP8266-based garage door opener). It’s pretty much finished and I will probably post it by this weekend as a submission to the ESP8266 design contest. The framework I’ve built for OpenGarage firmware (including the WiFi setup procedure and UI) will be a good foundation for writing OpenThermostat firmware.
@Ian: yes, your suggestion about making remote temperature sensor is a good suggestion. It might not be very economic to make separate temperature sensor nodes; instead, I can have some OpenThermostat units to serve as sensing nodes which can send its data to other units.