Need a thermostat to use average of temp sensors.

I have 2500 ft downstairs and it is always colder on one side of the house than the other. I wanted to install sensors to average the temps for the thermostat to use. Any suggestions on thermostat / sensor brands or model numbers.

The TZ43 Thermostat: - supports up to 2 indoor remote sensors - Remote sensor can replace internal sensor or provide averaging 8)

Are there any with wireless sensors to avoid the labor?

I have not seen any wireless sensors that go with a particular thermostat but you could look at the HSM100 sensor or the HM-TS001 - Z-Wave Temperature / Humidity Sensor and write code to do what you are looking to do which is temperature averaging 8)