Here's the complete proof-of-concept of an i2c sensor network.
It consists of 3 parts: the i2c slave sensor, the i2c slave gauge, and the i2c master "orchestrator". The orchestrator requests data from the sensor and sends it to the gauge. And it works! Yay! Go Arduino!
here's a descriptive video on youtube: http://www.youtube.com/watch?v=4gK2eJJHS-U
here are the sketches:
here's the hex: