For the past 20 years I've been somewhat obsessed with bike fit. I remember that I did the Fit Kit back in the early 1990s, and they came up with me riding a 55 cm frame. For the past 7 years I've ridden a 56 cm (center to center seat and top tube) and it has always felt maybe a tad too big for me. I've never been able to fully throw my seat back like I've wanted like the pros do, you know? And, I've always thought it was a top tube length problem.
This comes down to one major problem--I have
this to contend with. It necessitates a more cramped position on my bike.
But, then again, I'm reading about Petacchi's
bike and he actually just rides a 56 cm center to top. He has a REALLY long top tube, though, which, again, I couldn't deal with since my torso is actually a little bit shorter, proportionally, than my legs and because of my back problems. In the end, the bike that would suit me best is probably a 56 cm bike (c to c) with a 55 cm top tube. This would have to be some sort of custom build, though, and will probably have to wait until I'm well into middle age.
In the mid to late 1990s I rode a 57 cm bike that necessitated a very short stem, which made the handling quite odd. I remember riding down Hoosier Pass in Colorado, near Fairplay where I was living at the time, and not feeling stable going 60 miles per hour. Descending Mt. Evans after the race was even sketchier. This was one of the Trek Carbon frames (the 2300) before they really dialed in carbon manufacturing. By definition, it was sketchy.
I look weird on a smaller frame though. But that is silly--I think I can fit my new frame to be exactly how I like it, maybe by purchasing a slightly longer seat post.