If you were interested in making proprietary cogs as well, another option is to model the setup on the Miche system - a splined cog fitting on and then a threaded lockring just to keep it in place laterally.
Or hey, make a hub with a short splined section that you could slip a standard splined sprocket onto, and then also hane the threaded lockring section just outside of it. That way you do not have to manufacture the cogs (sprockets) or any other parts, you get the advantage of the relatively easy swap, and its one less threaded interface than the Miche (in reference to the adapter/hub).