"that depends on your definition of the word "large". Conceivably, we could build a really large capsule for such payloads. The question is why should we?"

Say you wanted to return 100 tonnes of lunar rocks to Earth per year.

Apollo CM was 5 tonnes:
"Crew Size: 3. Length: 3.47 m. Basic Diameter: 3.90 m. Maximum Diameter: 3.90 m. Habitable Volume: 6.17 m3. Mass: 5,806 kg. Structure Mass: 1,567 kg. Heat Shield Mass: 848 kg. Reaction Control System: 400 kg. Recovery Equipment: 245 kg. Navigation Equipment: 505 kg. Telemetry Equipment: 200 kg. Electrical Equipment: 700 kg. Communications Systems: 100 kg. Crew Seats and Provisions: 550 kg. Crew mass: 216 kg. Miscellaneous Contingency: 200 kg. Environmental Control System: 200 kg. RCS Coarse No x Thrust: 12 x42kgf. RCS Propellants: N2O4/UDMH. RCS Isp: 290 sec. RCS Impulse: 26,178.00 kgf-sec. Main Engine Propellants: n/a. Main Engine Propellants: 75 kg. L/D Hypersonic: .3. Electrical System: Batteries. Electric System: 20.0 kWh. Battery: 1,000.0 Ah. "
http://www.astronautix.com/craft/apollocm.htm

Suppose you wanted 10 or more tonnes lunar rocks per trip