I wouldn't say we will see an obivous spike in hashrate as I think they are still replacing previous generation hardware.  See for instance the S2, and UMISOO(S2) going offline because it is no longer profitable on Hashnest.

I'm just taking an educated guess, but I still think we see the S7 released in September.  Also to guess the price check out this thread: https://bitcointalk.org/index.php?topic=1159185.0