The other are maybe working, I hope they'll be back during the holidays but, if you really want to make a clan championship, I let you organize and find teams (5 players mnimum per team).
Create, as papunapu did, a topic for registration.
Then I'll schedule tournament and moderate it, no problem... but right now I don't play enough to find out teams and make ads for it.
So, if you want to do it,
ps : a big team can have 2 differents squads of 5 players (ex : evil 1 and evil 2)
The best defence is attack!