I'd WILLINGLY pay extra to travel with a 3 man crew up front, every time, no question.
I fear you're asking for something money can't buy. There is no need for a flight engineer and in any case the no3 would have to be a type-rated/trained pilot (albeit arguably no need to be current or valid medical). How are you going to find enough suitable people who are prepared to get up early, go to bed late and sit twiddling their thumbs every day? And where would they sit? The jump seat? Why not give them a rifle and make them wear a Stetson as well?