arduino - Sensor for ultralow (to -85°C) freezer monitor

I am planning to build a series of Arduino-controlled temperature-reporting units for a room full of "Ultracold" -80°C freezers. (I ultimately want to convert the signal to a serial stream that will interface with my existing system.)

So far I have only found one-wire and other sensors that are only rated to -55C. In my application they would spend most of their time around -80C. I only need about 0.5 to 1 degree accuracy at those temperatures.

Does anyone know a source for a low-temperature sensor that would be arduino-compatible, reliable, and be able to be placed at the end of a wire (to be passed into the freezer through a small port)?

Small update below.