@Jonathon: it’s interesting you mentioned that the box doesn’t need to be slick looking, because a stylish look is one of the main design challenges. Your suggestion actually makes a lot of sense — kind of like how sprinkler controllers don’t have to look stylish because nobody is going to look at it every day! I guess one consideration is that for most people who do DIY installation, it’s easier to replace an existing thermostat on the wall, than to chase the wires and find out where they go behind the walls. Also, the thermostat typically has a built-in temperature sensor and should be placed where it needs to sense temperature at. But that’s less of an issue as it’s better to separate sensors with the thermostats for better accuracy (i.e. the temperature sensed at the wall hardly represents the temperature at the center of the room).