I've organized some events on a local level with other games, but I see a couple problems with hosting competitive Splatoon in a tourney form.
There's no real way to match teams up. The only option is to join a friend, but the lobby can easily be filled by other people playing. If it's not going to be in a team format and it'll be based on consecutive wins, there's no way to judge that the games were fair. (Unless it's in a ranked format?). It could just be that one player was pubstomping people fairly new to the game. Not to mention, there's no way to spectate players in the game, so you'd have the view the cameras of each player. Even if there were methods to have teams play against each other, the physical limiations are present as well. It's not like Smash where it can be hosted on one console. There'd have to be a bit of funding to buy eight different consoles, each with characters at level 20 to play on a fair level. If not, then players would have to bring their own wii-U to participate.
As soon as these problems are addressed, I'll have no problem trying to organize an event or gathering for New Jersey players, but there are too many limitations to have a successful tourney.