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@J�rg:  I don't follow.  Unlike a rook, the rhino cannot confine a king to an edge without assistance.  In fact, it cannot confine the enemy king ANYWHERE without assistance--its attack pattern is porous.  The friendly king needs to stay close to the enemy king to plug the gaps.  It's not even clear to me that rhino+king could force the enemy king to an edge in the first place.



If you take the diagram nnz posted, the rhino delivers the check, so it must have been the last piece moved.  Which means the lone king's last move must have been from g8 to h8.

So:  black king g8, white king h6.  In order to force the king into the corner, the rhino needs to be some place that attacks both f8 and f7, and to deliver the checkmate it also needs to be able to reach e7 in one move.  That pattern of three adjacent squares does not appear anywhere in the rhino's movement diagram.  You can't rewind the position shown even one move.  Therefore, the rhino cannot force the exact position shown.

HOWEVER, a similar mate might still be possible; the rhino could also deliver the mate from c6 or a5.  A rhino at e5 threatens f7 and f8 and can also reach c6 to deliver the mate.  Perhaps you might also do better to locate the friendly king at g6 instead of h6.

So the exact diagram nnz posted is not possible without collusion, but I still don't know whether it's possible to force a mate or not.  My suspicion is not, but I haven't given it extensive thought.