I admire classic constructeur bikes as much as the next guy, but $560 for a stem? I choose to believe someone bought this to complete an original Singer that was missing the stem. The yen to dollar exchange being what it is, though, it's probably on its way to Japan to sit in a display case.
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT