I recently got a new 6 Plus and bought the Spigen clear light plastic back case. When it came, it said 6 / 6S on the box, so hopefully this case will fit the 6S Plus.
When is everyone selling their old phone? I'm going to wait until I have the 6S in hand.
They say that the 6/6+ soft cases will fit the 6s/6s+. But the hard cases will not quite fit the 6s/6s+. We will have to wait and see. All should be revealed on Wednesday.