I have not tried it. However, I am putting together a Duemilanove type board with the ATMega32U4, and I'm thinking the Teensyduino code could be good on that.
I haven't decided what to do with the extra 6 pins yet; I have going to a jumper block to allow I2C or A4/A5 to connect to the header, and put some parts in support the PE2 & PE6 pins. That leaves PC6 & PC7 still unconnected.
I have assigned the connections to the headers to maintain compatibility, this makes the layout work ok, not sure if the assignments make sense or how much pins_arduino.c will need to be revised.
