Looking for Diplomatic Adventures Like "The Prince of Redhand"

I'm looking for modules (or just adventures ideas) to make a multi-session diplomatic effort an interesting and satisfying experience for my players. Basically, I'm running a heavily modified version of the Age of Worms in Eberron and they enjoyed The Prince of Redhand. But now the party has returned to Zeech's court in Newthrone to celebrate his coronation as king of New Galifar and his marriage to his new queen (a previously killed party member whose body is being inhabited by a lich). Basically the party is attending to figure out more about their marriage, what Zeech and Lashonna know about the new queen, and to petition Zeech to send forces to Whitecliff (Alhaster) to aid them in the final battle. But at the core I'm looking for modules that have ideas to make the dinner festivities interesting without just rehashing Prince of Redhand. I came up with a bunch of NPCs including some old friends and have general ideas for duels and perhaps a formal debate. But beyond "Diplomacy" in Dungeon 144 I haven't found much inspiration for sessions like this, so any assistance is appreciated!

There was an old Mystara module called Mark of Amber, which was based on the even older X2 - Castle Amber. Mark of Amber fleshed out the castle, making it more realistic and taking out the gonzo elements from the original (which I always kind of liked). In addition to the detailed map/setting, it has an adventure which I'll let speak for itself:

Quote:

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Mark of Amber is the story of the battle for the soul of an Immortal being, Etienne d'Ambreville. The heroes are summoned to mighty Chateau Sylaire (formerly Chateau d'Amberville) on the eve of a major family wedding by the matriarch of the clan. Here through a series of dreams they relive key events in Etienne's life. The PCs' actions in those dreams determine Etienne's fate.

To make their task more difficult, the black sheep of the family, Henri, has chosen this opportunity when his relatives are all gathered together to begin killing them off one by one. Henri and his paramour Dona Carmina have kidnapped his brother Richard and sister-in-law Isidore, disguised themselves as their victims, and taken their place on the throne. Their task is made easier by the fact that everyone believes Henri to be dead: thus no one suspects him to be impersonating his brother.

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It's supposed to be for two to eight characters from 4th - 6th level and I think it's for 2nd edition, so you'd need to do a good bit of work converting and leveling it up to be an appropriate challenge.

I think the Kingmaker module for pathfinder has a fair bit of diplomatic schenanigans.