Sears sells a set of up to 1/2 inch (by 32nds). They are in a black steel box which is a little hard to open, but they are the best, best drills I have ever owned, bar none, including all the ones named above. Cost is around $60.
I had to drill a boat-trailer tongue to mount something and just picked a couple of non-Sears ones out of the drawer and shoved and swore for a while. I went back to the garage, fought the Sears box open, went out and zip! - they plowed through the metal the others would hardly make in a scratch with a nice, clean, burr-less hole.
I've used them many times since and there's just nothing like them.
USA? I have no idea. But they are the best, that I know.
Neil