I used to work for a cruise line and was out on a ship when my brother set me up with my LeMond. It's a 57cm, but he told me "this kind of frame rides like a 59cm".
I had him take some pictures of it against my old 58cm De Rosa. The bike looks small but rides big, for being considered 57cm.
This photo was after the first round of alterations - flipped the stem, re-positioned the brake levers, changed the seat, and put 180mm Dura Ace cranks on it.