I'm glad I found this thread, as I just purchased a new iPhone 4S with iOS 6 currently installed. The phone is brand new, never used, and I just got nervous wondering if when I take it to Verizon for activation on my phone line, will they (or the phone itself) force me to update to iOS 7.
I really hope not, since the reason I bought the phone was a last ditch effort to get back onto iOS 6 again. I'll sell my current 4S phone for roughly the same price I bought the new one, so while the process may seem cooky to some, it's an even trade for me and gets me back to my preferred iOS 6!
That is, I HOPE it will. If Apple or Verizon forces me to set up the new phone as iOS 7, I will be upset.
(Side Note: I don't mind setting up my phone as new. I can reload all of my apps and music through iTunes manually, and I'm willing to manually enter all my contacts again if it means I am able to keep running iOS 6! Can someone confirm that I can indeed keep iOS 6 if I set the new phone up for the first time?)