I haven't seen many fine point styluses, even in the threads quoted above. The Bamboo one is smallish, but nothing like a point. I know resistive touch screens use fine points, like the Nintendo devices. Capacitive ones need to conduct electricity and maybe that requires more surface area?
If you have anything metal with a tip rounded well enough (and just large enough) to not scratch the glass it should work. Conductive rubber on the end would be even better.