Would it not be easier to hook this into a multi-world plugin, so the arenas can be in a separate world. That way they could even be made from super-flat worlds, or people could swap their arenas really easily. Also: How about adding a voting system for the next arena to be used? Sponsors that can buy gifts that appear in front of the tributs? Gambling! Prize money for the victor! I like the idea of using factions for districts.