Twitter only from Arduino?

I am wondering if there is a way to access Twitter, namely to get tweets from a specific user utilizing only an Arduino Uno + Ethernet Shield? I am trying to turn on/off a thermostat based upon a command located in a tweet. I can tweet from the Uno/Shield but cant search for and get a tweet. I have registered for an app and have all the necessary tokens required for OAuth if necessary. I can NOT use anything else except the Arduino, realizing that it would be infinitely easier using a computer and something like Ruby to get the tweets and pass them along a serial connection. However this is simply not an option for this project. Thanks a ton in advance.

it would be infinitely easier using a computer and something like Ruby to get the tweets

If you can issue the commands from a PC, you can issue them from an Arduino.

If you can parse the reply using Ruby, you can parse the reply using C/C++.

"Infinitely" overstates the case, I think.

No my Ruby code for parsing tweets is all of 10 lines, the code to parse replies on an Arduino basically does not exist due to memory constraints. Not over stated at all