I guess that I own the one 16 gauge SxS that I've always wanted. It's an Ithaca Classic Doubles 4ES with two sets of 16 gauge barrels, the only one ever made.
It's got a Krupp steel barrels, Miller Single Trigger, BTFE, English stock and is drop dead gorgeous with it's Turkish walnut stock and fine Adams & Adams engraving.
Sorry, my photo skills aren't what I would like, but you get the idea.
Did I mention, it's gun #2 of a matched pair the other being a 28 gauge?