I still have Drone, which is basically 2 wheelchair motors in a metal box with wheelarches. It was designed as a sparring partner and not for combat, but there was designed to take a lot of punishment and is fairly heavy.

I believe there are 2 4QD NCC70 24V speed contollers inside (might not be, I would have to check), but the mixer is gone.

I will look for a picture of it. If interested I can take it with us to Fairford.