I've been giving Wilderlands' City State of the World Emperor some thought. It is arguably the baddest city around. If the original materials - the shops etc are available, link them to the master map. Then steal what seems useful in terms of flavor from Ptolus - much excellent material can be incorporated in this way as has been suggested on these forums regards Korsova, Cauldron, or any city for that matter. But then...
Why not Paizo's Curse of the Crimson Throne to inact the events that will occur if the Green Emperor dies? Sure, it would be Curse of the Emerald Throne, but Emperor's concubine (or queen, I can't remember original write up) could easily take the place of the queen of Korsova in the adventure path. Augment and change for locale and you would have mechanism worthy of driving the finest and greatest of all cities in the Wilderlands.