Two thoughts:

1) a sloping top tube provides the geometry for a longer head tube, which means more distance between the headset top bearing and bottom bearing, and, intuitively, this seems stronger and allows a lower stand over height for a given head tube length; and,

2) the smaller frame requires a longer, weaker, heavier seat post, and the whole idea amounts to a meaningless styling gimmick.



The above said, the bikes posted by potus and plantdude look beautiful to me.