Thanks, #1 has been what I've been doing so far. I'll have to think about how #2 and #3 would work in my context (fairly small company).
Honestly, smaller companies are not the best places to get into management because there aren't that many people to manage.
The key point is that you create a conversation between two people about your management potential. That way it becomes a social fact, as opposed to just a thought in one person's head, who may or may not act on it depending on how much they like you or want do to you a favor.