OP - As a single pilot 'enthusiest' with the waiver in 6 different Citations....I have pondered a number for design 'upgrades'....folding wings...more aerodynamic cockpit...etc..
The reality is that manufacturers are motivated to make money...and do this by selling planes to willing buyers...and willing buyers currently are not hiring and PAYING ex military and high time civilian pilots but generally chief pilot culled kids, marshmellows, over the hill hacks, ect...thus....they need docile, slow, stupidly overbuilt, way to many avionics to hand hold and keep the idiot pilots(that means two) out of trouble.
The point being...YES....I have considered a design with one pilot in front and maybe a rear seater.....maybe someone like the SR71 that would haul ass, with a pay load of say 8 people in the hold, two pilots up front in tandem, getting the drag cross section way down.
But it won't happen as long as the people who buy plane currently hire from the bottom of the resume pile rather then the top..
Hence why the planes are so slow, have so much drag, and have so much gear to tell the pilots where they are. It's sad..
Anyway...build that plane, I will fly it.