It would be nice if there was one. Maybe like a shrine or something where people can light candles for those who went missing or never came home and it remains a mystery. It must be agony.
The memorial is for all of them. I would like to point out that some POWs show up alive many years after the wars, sometimes 50 or more years. Rumors of surviving POWs in Vietnam continue to this day.
US Forces Listed Missing: http://www.dtic.mil/dpmo/wwii/reports/ http://www.dtic.mil/dpmo/accounted_for/