I know there's a "Pet Battle Guild", but for those of us that would like to stay within our own guilds and talk/trade/battle among others, why not set up a WarcraftPets do Com Battle Royale night? as long as one person hosts a 40-man raid they would all be on the same server. Unfortunately, besides bragging rights, there wouldn't be any "prizes" to hand out if we did a tournament unless people had pet codes to give away. We could all meet at an arena-style location like the "Ring of Blood" in Nagrand, etc.
Edit: I forgot to mention should pitch in for a night that works best for us like Wednesday or something.