You can do better than to provide a cheap copout!
You tell above "adding an intermediate set of gears between 1/500 and 1/1000 is an elementary task".
Should you have been true to the spirrit of engineering (and you claim having invented an analog laserdisc on other thread, and write from the "engineering standpoint!" here), you would have found out first how a vertical FP shutter like the Copal Square works.
If you had, then you would had ealized that:
- You don't need to add any "intermediate set of gears" for adding any speed above the sync speed which is 1/125..
- The way the speed selection works at the aformenetioned speeds, internediate speeds is the natural outcome, not a special feature.
Now bye bye, I don't want to keep this thankless task of helping you out in things that you should have researched first.