Yeah it is an interesting idea. It's something that Schumacher tried out on the touring cars a good number of years ago (2003 ish i think). From what I remember, it gave a slightly different diff action, and I seem to remember there being more "wear" on the plate on the inner track. Never did work out why, and we went back to all the balls being on the same PCD.
http://www.racing-cars.com/pp/New_Ca...Mi1/U2445.html