Does anyone else build such gyro stabilizers?
No, not like ours. Most gyros, either unhoused or housed, contain a single wheel and thus only one axis is covered, the only relative similarity is the image stabilized lens- here the physics are the same but the IS lens uses tiny gyros to act on a prism to change the line of light in the lens. We use larger wheels, such mass in our gyros will stabilize the whole camera or binoculars, not just the line of light into the optics.
