Hi Nick.

I think is a room for a belt kind of panohead, to have a small rotator with 3-6 stops, different design from the current rotators as the interior side must be the one who rotate, so is the kind of rotator which is atached to the panographer's belt, has a telescopic segment up to 1.5 m, and in top is the lens ring.
The rotator can be smaller as is not requiring extreme precission, still in action panos and journalistic VR the stops are of great help.

cheers,
Dorin
www.livepanoramas.com