I had a thought regarding a pvp clan tournament / war that I wanted to put out there for consideration. 

Basically it's a type of salmon ladder. The idea being that each play gets 3 attempts to climb a ladder of an opponent clans pvp teams. Once the player loses a match they go to the bottom run of the ladder. They can choose a new team and attempt to climb higher up the ladder. The clan with the highest over all progress wins. 

There would need to be some thought in to balancing to ensure that the best team doesn't get placed at the bottom preventing low level players winning any matches. Possibly the order could be set on player power with a max number of players