I saw this circulating around and thought it was an interesting read.
Some of these are horrendous, some are funny, and a few made me think "Hmm, maybe not a bad idea"
You could always just make something below cents and make 1 cent = 1 billion of that thing. So $1 would be equivalent to like 10 billion dollars. Granted, somehow you'd have to invalidate existing currency and push that type of policy in a political environment that is able to pass a constitutional amendment to prevent wealth accumulation. So, it couldn't possibly be that extreme.