I've been busy with the prototype and I an say I'm happy with the work done. I have the prototype (see the attached project photo) communicating with misterhouse (room temperature, humidity and I can poll the status of the traffic light - the Red/Yellow/Green LEDs). Misterhouse is now sending the commands to change the traffic light (8 seconds, green, 4 seconds yellow, 8 seconds red). This works very well but found out 2 things. One: Mosquitto 1.4 is a bit buggy and Two: that MQTT QoS is on the subscription side. Now I have to figure out what that means to my varius programs.
I know I don't have much here but actual progress has been made on the project. Th MQTT client is based on my work on my Smart Lamp node. So I'll start adding the parts list here shortly.
My initial work will be based on the WIZ550io boards I have working with the UNO32 and Fubarino Mini (PIC32) processors. I have several ESP8266 board (-01 & -12) but just got the Arduino 1.6.5 env running with the ESP board. While I could use the ESP as a stand-alone board I'm envisioning the need of 2 processors. One for the networking and the other for general processing. If there is enough processing (and IO) power in the ESP8266 boards I'll post those in another project.