chriskner:
I2C Scanner will not work as expected with the DUE.
endTransmission is flawed with 1.5.1r2
See:(I2C) Wire.endTransmission always returns non-zero. : http://arduino.cc/forum/index.php/topic,144700.0.html
-Chris
Whoa... thanks for the info. This is definitely a non-trivial issue then. I might've waited on the Due had I known that something as fundamental as I2C isn't actually working yet.