We can have individual templates for each board, so it seems only natural to extend that feature to other areas such as rank. This would benefit forums that house many different projects with unique identities (a game/mod hosting site with a group forum for all hosted games/mods, or a group forum for different comics/artists, etc).
This could be defined inside the ranks, with a collapsed list of forums (like in Search). By default, a post rank is considered Global, used across all boards, but by expanding the list of forums you can determine where it will be visible. Therefore, you can have multiple ranks at the same post level, but utilized on different boards.