Hi /u/MajesticAlot, we do not yet have a private tribe option but it is in the plans.
Is there a list of "is in the plans" things? reading this thread I've seen mobile apps, private tribe, and a bunch of other cool things. It'd be neat to see a list with, if I'm not asking too much, progress reports on separate items.
Furthermore - is there or will there ever be any plans into making Snapzu open source?