Yes, it is more or less similiar. I also see now that I got a bit carried away
, because what I proposed has more to do with snapping and horisontal movement than constrained vertical movement. But the two are related as long as the vertical movement involves snapping.
In FCP, it is possible to shift+drag to move vertically. Also, one can select a clip (by clicking on it) and use the keys Alt+Uparrow or Alt+Downarrow to move clips vertically.