So, I have ordered a 4WD DFRobot body and assembled it. On top of it I have mounted a Fez Panda, 2A Motor Shield, SD Card Shield and a Xbee Shield.
Also mounted is a 9DOF IMU, GPS Module and Ping. I will be using 3 COM Ports (Xbee, IMU and GPS). I haven’t worked out the Ping connection, how I will deal with the encoder signals and the servo. All of which right now are not that important.