My understanding is the Icon is just the Verizon version of the 930 (or the 930 is just the GSM version of the Icon, however one chooses to look at it) so if, in fact Verizon has some sort of exclusivity agreement, I'm sure it includes not offering the 930 through other US carriers for a time period. Again, all just assumptions on my part based on past scenarios.
I hadn't looked specifically at the 930's frequency compatibility so if they did include LTE compatible with US carriers, that's great news. Unfortunately, we generally don't see unlocked devices available at retail outlets and only occasionally via online stores so it'll likely be a bit more expensive if import is required. I really do hope we see it here as it's the first WP device that really captures my complete interest. The 1520 is a great device but just too big for my tastes.
And sadly, outside of the Xperia Z1S (an exlusive version of the Z1 for T Mobile that was released months after the global release) and the Z Ultra GPE, we haven't seen recent Sony offerings (Z1, Z1 Compact, Z2). And no announcement of future release dates either.