According to sUAS News, Boeing engineers have suggested a 165% scaled-up version of the X-37B space drone for manned spaceflight. The cool graphic below shows two configurations each with five or more astronauts.
My original Traveller X-37B design was only five dtons. Scaled up at 165% makes it roughly 8.25 tons. In both designs it looks like the all “cargo” is replaced by “crew.”
(EDIT) Here is the ship card from High Guard Shipyard (HGS 1.20.17) using Book 2 design rules. A few obvious problems are the automatic fuel scoops and the 1 dton of fuel.
Ship: X-37M Class: X-37B+ Type: Shuttle Architect: Boeing Tech Level: 8 USP XM-0101101-000000-00000-0 MCr 7.640 8.25 Tons Bat Bear Crew: 6 Bat TL: 8 Cargo: 1.250 Fuel: 1 EP: 0.083 Agility: 1 Fuel Treatment: Fuel Scoops Architects Fee: MCr 0.076 Cost in Quantity: MCr 6.112