There are 24 large villas, with 2 more houses evolving to Large villa as the game continues, plus 5 medium villas. I'm uploading this earlier save, because I triggered victory too early. The rest lives in (again, in some instances soon to be) large insulae.
I know that feeding bigger population, maybe even 17 or 18 k is possible, but with the scarcity of second food, they would all have to live as plebeians, with high unemployment.