bezel down:
Clickies have a good bezel down option
Rotaries dont have a nice bezel down option.
U shaped clips for bezel down:
The Legacy clickies with clip holes in the head, achieved bezel down carry by using a U shaped clip.
For a Rotary to be clipped bezel down, with a clip attached under the bezel, or screwed to the bezel, or to holes in the head, would also require a U shaped clip.
bezel up:
A bezel up option (clip under the bezel) already exists for both Rotaries and Clickies, but Henry officially discourages it, and I think the only people that do it, have Rotaries. It is not a deep carry setup, and the diameter of the clip ring is greater than the diameter of the light, not ideal.
As thermal guy suggested, if the HDS bezel had a clip screwed to it, it would allow for deeper carry for those wanting bezel up.
I think the majority prefers bezel down carry though, so the rotaries would need a U shaped clip.