The problem is how tough it is if you can't actually standover a bike's top tube. It is at best awkward. And, the secondary problem, which seems common with touring bikes, is the very long effective top tube. For example, if I used the Bike Hermit's seat of the pants calculation for effective top tube sizing I would need a bike with a 46 or 47cm top tube. There aren't any off the rack adult bikes that "short." This is probably why one of my bikes ended up with a 60mm stem and another a 50mm stem. Seat tube angle fits into all these measures as well as I understand every one degree of difference creates a one centimeter difference in fore and aft position.
Trek Madone 4.7 WSD
Cannondale Quick4
1969 Schwinn Collegiate, original owner
Terry Classic
Richard Feynman: “The first principle is that you must not fool yourself and you are the easiest person to fool.”