I'm guessing (hoping) we don't see an S8 until July of 2016. I would expect we'd see something like 8TH/s @ 1250 watts.
interesting to think the s-7 is only 60 day old and we are talking s-8
the s-7+ may have 4 s-7 cases slide them together use 2 boards each with 2 heatsinks each. 8 boards slight downclock = 8 x 1500 or 12th but .2 watts or 2400 watts.