Umm... if I'm searching correctly, that's a $350 thermostat. What I really need, is an ethernet connected remote temp sensor.
Under $100 all over eBay.
I've done a lot of home automation and I've never seen a wired stand alone temp sensor. Plenty of sensors that will wire to a thermostat, but you also need a stat capable of accepting a remote sensor. The 824 does both.