Well, my interests are purely for my own desires for my SO, open providers, and I have a great time together at my place. But once I've had some fun, I could see selling a machine or two. Maybe there's one or two dominatrix providers that would be in the market.
That being said, I'm thinking a machine with a 7" lateral stroke that turns back and forth a half turn per stroke with a max speed of 300spm. Toss a firm flex joint on the end of the shaft as well as two positioning actuators that can bring the end up/down/left/right using the joystick controler. Then a Vibrating dildo on the end and I feel that it would deal some serious body convulsions and hopefully some squirting