I was just having a conversation on this very topic with a friend of mine the other day. Not military dog tags, but about people who always wear bluetooth headsets, whether or not they are on a call.
I'm talking dinner party with one of these things hanging off an ear lobe all night long. But enough ranting, the Jabra BT-3030 turns any set of headphones into a bluetooth headset. Plug your headphones into the dog tag and you have consolidated music and phone control without being that guy
Available here for $63