Yea, I was wondering if there has been or are any bands where there is a dedicated lead vocalist, but that person isn't the frontman. When I say frontman, I'm thinking along the lines of the one who does most of the interacting with the audience between songs and leads things along.
One band where this might have happened, but I don't really recall, is when Nugent didn't do lead vocals. I can't remember the lead vocalist's name...St. John or something? Anyways maybe Nugent was the frontman, or at least shared that spot?
But you got the idea of what I'm getting at.