After reading through Rogue Trader, and in particular the Kronus Expanse, I've become intrigued with Port Wander. The "Gateway to the Expanse" is a gem just waiting to be polished and placed in the crown of almost any campaign.
A place of desperate hopes and vain dreams; Port Wander teems with a transitory population of traders, spies, merchant factors, pilgrims, and missionaries amongst which move Administratum functionaries and minions of the Mechanicus, all feeding on the riches that flow from the realms beyond the warp storms in the Koronus Expanse.
So in your game, what characters, what plots, what contraband and what ships do you have passing through Port Wander?