If you happen to have Filtrete 3M-50 Wi-Fi Thermostat, you can now connect it to SmartThings. They used to sell at Home Depot for $99, but now seem to be discontinued.
I used to have it integrated with Vera, but since I switched to ST, I could only control it remotely with the Radio Thermostat mobile app, which is, by the way, very well done. And now, I have fully integrated it with SmartThings.
The source code and installation instructions are available here:
Note that like most Wi-Fi devices, it relies polling, thus installing Pollster is highly recommended. If fact, I wrote Pollster specifically for this application.