From what I can remember:
Action VI - 4 (possibly 5)
Modular Conveyor - 7
Simiyiar - somewhere around 10
Don't know about the others.
Horizons have quite a few rooms plus the ability to carry a ship and a vehicle but they're expensive. From what I can think of right now one of the best for price:room ratio would be buy 3 Sprints and squad them together, 12 rooms, close to 150 passengers, 6 medical rooms for less than 10m if you shop around.
There used to be a website with a library of the room maps. And also someone in commerce section selling them. I should upload them on my website sometime.
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Benedicta Per Gratiam Jou
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