I am in San Luis Obispo, CA and mine is the only one I have seen. Being at a software company I was sure they would be more prevalent, but everyone seems to be on the Android kick, lots of HTC's -- mostly the manager types. Trapped in Java VM over a linux kernel, they seem to have missed the point, entirely. Very surprising to me. Have not seen one anywhere else, ever... actually. If I see someone else, I am certainly going to strike up a conversation.