Not much to it. I suggest that clans should be able to truce (not be able to hit each other). This would be helpful if you wanna make your own clan, but you still don't want another clan to hit you. (Of course the other clan would have to accept the truce.) This would also be helpful if a friend's clan is full, but he still wants to truce with you. Support: 11 Neutral: No Support: 2 EDIT: It was suggested that clans can only have 1 ally.
No support, if too many clans are truced it will become so much like factions. It would be like a massive war and I wouldn't like it like that, that's why we have clans.
Support! Isn't there something like this on factions where you can make another faction an enemy/ally? Edit: Like Alma stated there could be a massive war. To prevent this make it so clans can only have one ally.