Never heard of "Dipole Gravity". (Of course there are so many "I want to be famous, so I invented a 'theory'" type theories of gravity out there.)

Of course, if this "researcher" has to ask why there is no shift in the center of mass of a rotating sphere (as opposed to the rotating hemisphere) then I have to ask whether he has much in the way of understanding. Since I presume the rotating hemisphere is rotating about its axis of rotational symmetry, then the answer is simply the fact that the sphere has an additional mirror symmetry perpendicular to the axis of rotation, through the center of the sphere. This symmetry alone precludes any such shift! (See, so simple one doesn't even need any calculations, and the result is theory independent.)

David

P.S. Of course you'll probably claim I'm one of the "crooks in the field".