@ted-miller I did this some time ago. I also had to tweak the Motoplus driver a bit to make this work, especially in MotionServer.c I added this:
// first robot
moveData.ctrl_grp = 1 | (1 << 2); // AKo: Hard coded special value for our SD10D R1+B1 R2 special configuration
ret = mpMeiIncrementMove(MP_SL_ID1, &moveData);
But yes, with these changes it is definitely possible to operate all 15 joints of the SDA10D with a DX100 controller simultaneously (run whole body motions).
We at Xamla added a couple of more things to the Motoplus driver for better realtime control etc, e.g. see FT control or joystick control. In general an issue of the DX100 is the big latency of the system (~ 100ms) which is probably caused by lower level moving average filtering in the motor controllers.