It's way early for this, even for a slow forum mock. You're going to have a lot more luck asking around January. That said, I don't think you need a whole forum - just a thread somewhere if you manage to gather 12 owners, and are willing to keep track of it.
I could be wrong, but Arlo is always very busy so trying to get a forum for a mock this early on may be impossible. If it goes down, though, and it is a mock and only a mock, I'll be part of it.