I've settled on military type dog tags (i.e. necklace) with (1) full name (2) city, country, ZIP (3) ICE phone number (4) ALT phone number (5) phone number (Europe has more digits so I couldn't fit a label on the line).

I had considered RoadID tags mounted on a watch bracelet, but they are four+ times the price of what I've found here, and perhaps a metal plate on a bracelet isn't such a great idea anyway.