The shortest are on my current full cap is probably 1/16", believe it or not.

Before you say "Oh man....that's AMAZING!" keep in mind that this is directly above the ears and it tapers quickly to 1/4, 1/2, 3/4, up to about 1 inch on the sides, then the top is about 2.5 at its longest.

I know what you mean with a topper. When you have to make it blend with existing hair the shorter you go the more difficult it is. i would say you're doing good if you can get it to 1".

Now that I have some experience with using a hair relaxer I would bet that it would be possible to bend the hairs in the right direction if you were to get unruly hair when it is cut short, but I wouldn't want to be the first to try it. I think you could do some crazy stuff with it if the hair was in good condition, but it would take a lot of practice to perfect the art.