Thinking outside the box.
High Speed Helicopter ~ US patent 4,720,059
The 'Abstract' of the above patent says
".... a tiltable mast which is located a substantial distance off to the retreading blade side of the fuselage of the helicopter. This causes the fuselage to be located completely under the advancing blades."
Hoyt Stearns has two or more patents and has made at least one presentation before the American Helicopter Society.
The above concept may, or may not, be valid. However it does provoke technical thought; just as Lu Zukerman's posts used to provoke lively and interesting threads on this forum.
Mr. Stears can be contacted on another Rotary Xxxx Forum, if desired.
Dave J.