Originally Posted by repechage

I think that the "flick-ability" of the Cannondale may be the front center dimension, not the frame size of the seat tube, and maybe the head angle too.

From your description, I would look at some frames from the late 40's or 50's, often they have much longer top tubes than what was to come in the 60's and 70's. The 80's was shorter still for a given frame size, I am making generalizations here but bikes have been getting shorter over the decades.