I'm liking this idea more and more. I think we'll be implementing this after the change to 1.2 on a multiverse world. The votes (as they've stacked up so far) lead me to believe we'll go to an FFA all out war server until 1.2 comes out. Fire spread, tnt damage, and no place to hide. Prepare for frustration, or prepare for domination if you form a good enough alliance. Yes, allies are allowed.