MotorMate is expandable with MotorMix2. Fro example Protools supports up to 32 Channels of CM Labs consoles. 
Exclusive to our consoles, MotorMate and MotorMix2 can actually be mechanically connected together to form large single unit consoles.
You can set their units together on the table, but they cannot be connected like MotorMate and MotorMix2.