I think it would be sick to have a game-mode where it was mainly dedicated to clan versus clan fighting. There are 3-4 teams or so and your entire banner gets put together, no exceptions, no autobalance. You and your clan can fight for dick-size and dick-waving rights and shit. I think it'd also be fucking cool for "trying-out" new possibly additions to the clan, so to speak. To see if they're worth their salt in a fight and would be a good addition to your clan. Maybe you could pick the team you're on so clans that have really close ties could hang out on the same team. I know that FIDLGB and Chaos are tight bros, so if it was possible in such a game-mode, I'd pick to fight with those folks.
With some sort of queu implemented? It sounds kind of lame and "wowish" but with a system like the dueling one but with "clans" or "teams" we could have something like rated battles, say points per "round won".
And this would do clan activity good, ofcourse it has to be balanced and to make it work good custom maps will have to be made that are build for the gamemode, only random plains would work atm with 4 spawn points im afraid...
Im very stoned atm so im not sure wether im talking crap or not
Ps: no xp/gold reward, maybe x1 but no multi, just rating, if won this should really be about the gameplay not raking money and xp.