Not always. And you can see some folks doing this like the VO Campeur and Rivendell.* There are a few other folks doing it as well. Geometries as far as effective top tubes can also be manipulated with the head and seat tube angles as well as taller head tubes with sloping top tubes. As far as frame size, I know we've talked about this on here before, but a numbered "frame size" on a bike is totally irrelevant. I've had a Schwinn "labelled" as a 53cm with a 57.5cm effective top tube and a 90mm head tube and I've had a Motobecane "labeled" as a 53cm with a 53cm effective top tube and a 120mm head tube. I can tell you right now that both of those bikes would not fit the same person proper. That is what is so frustrating about sizing. I feel for the guys coming in and insisting they are a 53cm for example when I know that it will take all the measurements on a frameset to get him fit proper. How many times have you read that a guy bought a certain frame size on line or what not only to realize that it came nowhere near fitting him comfortably. BTW, I was incorrect on the particular Surly. It's the Cross Check that has a crap geometry. I cannot speak for the Steamroller. Sorry for the error.
*more so Rivendell