This would be a smutty space opera in the Third Imperium setting of the various incarnations of the Traveller
SF RPG. We could use some version of the Traveller
rules straight up, strip the rules down for ease of play (and especially ease of character creation), or just use the setting and go freeform.
A youngish member of the Imperial high nobility borrows one of Daddy's starships for a year-long interstellar joyride. With him or her are a number of rich ne'er-do-well friends, a couple of servants, and the ship's hard-working crew. Where will they go? What will they see? How will they pass the time while the ship is isolated in jumpspace?
I'm volunteering to GM, and probably play the ship's captain as well (that's the head of the crew, not the noble whose starship it is—I expect that role to be taken by a player). Between passengers, servants and crew, the game could easily take a dozen players, or could run with only three or four. I'm expecting mostly humans, but a few aliens or genetically modified humans are possible as well, within the constraints of the Third Imperium setting.
Let me know if you have any interest. (If you don't know anything about Traveller
or the Third Imperium, Wikipedia actually has a pretty good description