Just got back from the Apple store. No iPhone 4S' there, of course.
But I did get one question answered:
I asked if I got the Verizon or Sprint 4S, would the GSM side be locked?
She went back and talked with someone and the response was:
It will be locked in the US, but anywhere else it will accept any local micro-SIM and work with GSM.
Now this is just one answer form a blue shirt, but at least she didn't say yes off the top of her head.
It's worth checking into this deeper, because this would be a BIG plus for me. I travel and would love to use a local SIM instead of deal with high roaming and figuring out the international data packages the carriers offer.
The way she described it, it's also possible that it's only locked to AT&T in the US, not internationally. So in the US, it's locked to one of the three carriers. But outside the US, it's unlocked.
Thoughts? I'd love to get some additional confirmation on this.