Gitzo had a good idea with their 2540lvl with a built-in leveling feature. I very nearly bought a couple of days it until I worried about the rubber seal I saw between the ball and the outer ring.
Leveling at the base of an adjustable column might be a better idea from the point of view of center of gravity than leveling at the top.
I am comfortable with my choice of a "second" panning plate mounted atop the ballhead, although that acratech leveling base deserves to be checked out.
I think that the minimalist concept head is something like the acratech leveling plate (or gxxxxlvl tripod) topped with the rrs pano clamp.
At that point you can go the whole way if you choose as rrs illustrated here
http://www.reallyrightstuff.com/pano/07.html
At that point, the ball head would be redundant. I shy away from all of this since mostly all I need is a simple ball head and the stability of that stack of lego bricks worries me somewhat especially with heavier gear and longer lenses.
Using a "regular" tripod topped with an rrs ball-head equipped with a panning clamp adds just enough pano versatility for me (knock on wood).
-bob