From the limited testing I've done, each tamed wolf prevents another animal from spawning. On my server this is a real problem obviously, cloth is suddenly very valuable. Enough players tamed wolves to the point that nothing else can spawn. I had to wipe them all out, and it was not a pretty situation. I thought of using MobLimiter but that would result in people fighting over wolves. Ideally I want to make it so tamed wolves just dissapear after the owner is logged out, I think that would solve it just fine.
Yeah I can do that in WorldGuard, and it might come to that. I was just hoping to avoid resorting to that. One more thing, If someone made a plugin to limit how many you can tame, that wouldn't solve it either since there would be wolf entities just blocking animal spawning even when the player is logged off. But how about having tamed wolves despawn immediately, and when the player logs back in, just have them spawn right at the player's location. There might not be hooks for any of this in bukkit though, but I'm just putting it out there.
For what it's worth, /butcher currently slaughters all of the tamed wolves, along with everything else.
http://forums.bukkit.org/threads/me...en-they-die-spawn-wolf-permissions-670.11486/ This is a plugin that will be adding support for this in the near future