I'm Thinking in making the jump to piratic adventures in Mordheim, there are rules aplenty in the web, and combining them with the general's compendium naval rules we could have a new and exciting background for the fights while maintaining the lustrian feel.
Searching in the old GW webpage I stumbled upon rules for settlements that gave three possible places to set as a base for your warband in Lustria: New Luccini, a tilean settlement, Santa Magritta, an estalian settlement, and Skeggi. The one wich is described as a "den of pirates and thieves" is New Luccini wich will replace Sartosa in the city fight scenarios.
The old page provided a colorful description of the city, including a brothel made from a shipwreck "the shore's whale" and a tavern with a slayer pirate inkeeper and an ogre thug: "The silent Parrot" ideal for the last orders scenario of Mordheim-Sartosa.
The city is located on the cactus coast without anyy specifics, I looked upon the map and it seemed to me that the best place to build a city would be the tiny peninsula below Quetzl island. So I grabbed a peninsular city map from the cartographers guild and with photoshop I expanded the walls (wich only covered the ithsmus) to envelop all the town, with the harbour protected by a chain.
In order to bring this city to life, I plan to restore my imperial buildings, finish a house kit from old, create the shipwreck-brothel, some piers, and even add some fields, since the map is full of them.
For the piratic campaign I'll also build a pair of ships for the two warbands and perhaps some islands?
Here's is a pic of the original map: