The idea of setting rank structure in clans is pretty intresting but then you will have In-Fighting about who's better than who. Atleast it will keep the "1 day clans" to a minimum. As far as ranking clans... It would be intresting. You might as well start a ladder and devote a certain set of servers aside for "legitamate" matches. Then with that you will have to set rules everyone will have to abide by during matches. Then you will have to dedicate someone to either ref the match or have someone review the game when there are problems such as disconnects and capping on idles. Committee!!!!
Thnx,
The Unknown Player