Well, you can grab a collection of frames and see if some pair measures up to the same geometry, but there are going to be variances in all the measurements (lengths and angles), due to anything from manufacturing tolerances to different thermal expansion properties. Then you look at how different builders focus on different styles (like longer top tubes for a given frame size) and the combinatorics start to get in the way of finding an exact match (or even +/-0.5mm).

What I'm getting at is that we can't get hung up on the feel differences between two frames being just due to geometry. Even if two frames have identical geometry on paper, it's unlikely that they do as measured.