It's a question beyond the scope of this thread, but I think a lot of it is buyer self-deception and sales department numbers games. People say they want a four-place airplane but rarely fly it with four people, so it ends up being a two or three people plus baggage application. Sales departments know that they need to compete on the speed and range numbers to sell airplanes, and a true four-adults-plus-fuel-and-baggage airplane would look stodgy on paper. Here's a homebuilt, wood-and-fabric example, though it's a low-wing design:

**Peña Dahu**
Wingspan: 9 m (29 ft 6 in)

Wing area: 15 m2 (160 sq ft)

Empty weight: 600 kg (1,323 lb)

Gross weight: 1,200 kg (2,646 lb)

Fuel capacity: 200 litres (44 imp gal; 53 US gal)

Powerplant: 1 × Lycoming O-360 four cylinder, air-cooled, four stroke aircraft engine, 130 kW (180 hp)

Propellers: 2-bladed metal constant speed propeller

Maximum speed: 310 km/h (190 mph, 170 kn)

Cruise speed: 230 km/h (140 mph, 120 kn)

Stall speed: 80 km/h (50 mph, 43 kn)

Rate of climb: 6 m/s (1,200 ft/min)

Wing loading: 80.0 kg/m2 (16.4 lb/sq ft)

What's interesting to me is that weights and power are basically LSA numbers x 2, which makes sense if you actually want to carry four people and their stuff. Payload with full fuel is 457 kg/1005 lb, so you could actually carry four adults and their stuff. The kicker is that you won't win any races because you need a big, high-lift wing and low weight -- cruise speed is 140 mph.

I don't honestly know, but I have never seen ANY sub-200HP four place airplane that can carry 4 full size adults and any fuel - legally.