You may want to look at some French frames. For example, my Gitane TdF has a 57cm top tube, but the ST is 57cm c/t, or only about 55.5cm c/c. As a generalization, Raleigh seemed to like much longer ST than TT, while many Italians frames are either square, or 1cm shorter TT than ST. Of course, all this varies by builder, and even within their lines.