I recently had the fortune to work with Ron Nelson from Seven Mile Mountain. Ron builds small, affordable controllers for various uses. I was looking for a physical joystick to control the Orb feature of Omnisphere and purchased Ron’s SOLO : USB MIDI Control Change Joystick on his Etsy store. It seemed the ideal solution for a straightforward and tactile way to interact with this area of Omnisphere that up until then I had mostly ignored. The controller arrived and I began playing with it, but the movements on the joystick seemed to not correlate at all with the changes in the software. I contacted Ron and we began conversing about my specific use. This issue was that the joystick transmitted Cartesian coordinates, whereas Orb needed to see Polar coordinates. Ron completely reprogrammed the controller and added several new features including the option to send both Cartesian and Polar data. Very useful!
Ron is planning on incorporating this into future models, but in the meantime you can contact him, tell him what you’re looking for, and I’m sure he can create a pre-production model for you pretty quickly. It seems to be one of the few hardware options out there that will work for this purpose, and it is certainly the best priced. Here’s a video that explains the build.