New faction idea

In most 4x games you always have some sort of "Cities" some times there really jsut cities and other times there planets. But I'd love to see a faction that operates on a gaint "Citadel" Like space ship. I know the Vodyion kinda already do this, but I mean the whole faction is limited to one gaint space ship. The city can even Function as a behemoth. This faction would be at a disadvantage. To balance this the faction could be a mix of all other races and or disgise its self as an other faction. That way it seems like your talking to the Riftborn but your really talking to this new faction! The faction can do this becouse it only has limited members of its real population and has to convert minor faction civilions or major faction civilions to join them! As for the base states of the "Citadel" you can have it stay in a system and reap the benafits of one or two of the planets in the system. This will make the City weak military wise and at risk of both spies, and being attacked! With this players will have to be careful if they should stay put and try to get some production going, or to move along before the other players figure out who they really are! I also personally think there is a perfect faction in the endless games that would fit this type of faction, and thats the Cultist. I love there disgen and feel like they would totally rock a gaint floating manican face city space ship!