I think there are some small scale commercial ones tailor made for ROV usage.
But generally, a teensy microcontroller setup as a HID (human input device) can easily be programmed to read buttons, switches and joysticks in ridiculous quantities at quite a low price. DIY project, but that might suite some!
https://www.pjrc.com/teensy/td_joystick.html
A forum user and distributor (?) might still sell the cadillac of controllers: http://www.deltarov.com/new/product/hand-control-unit/
Surface Controller - #254 by etienne