Please allow for the following formats.
1) A ladder format, where the bottom player on the rung has to fight the next person up, then the winner fights the next person up, and so on.
2) A "parallel ladder" format. This is what is used in Magic: The Gathering top 8 tournaments. See attached image.
The point of both of these would be to use after a top 8 cutoff of swiss. So we'd have swiss to get a top 8, then play into one of these formats to determine the winner.