That could be really interesting. I'm not sure I know how I'd want it to work, though. I think it's one of those "I want to see what someone else comes up with, and that'll give me a ton of ideas on how to 'improve' on what they came up with."
I still don't think I've done a social Skill Challenge in this campaign yet (though I have in my RPG, multiple times). I think I know when it'll first come up, but we'll see. It'll be interesting to play it out, at any rate
Ah, you've just reminded me of my negotiation skill challenges. I've run one once before and it went OK, that was when I developed this formula for negotiation challenges...
Create a list of questions that an NPC will ask the PCs, and require 1-3 successes per question, depending on its complexity. For each question, establish about 4 possible responses, half via skill checks, half automatic successes based on saying the right thing, calling on previous adventure details, or using an especially suited power. Then include a partial victory condition, in addition to victory and defeat.
For example, in the adventure BEAST OF BECHAEUX (which I'll upload soon), at one point the PCs need to track down a white-eyed elven assassin and have 2 leads: The menacing elven Alder King or the treacherous human Lord Polding. Both are negotiation challenges with a distinctly different feel. If the PCs decide to deal with Lord Polding, for example, his first two questions are:
1. Are you lot trustworthy, or will you sell me out to the Duke? (requires 2 successes)
- Have a token of his bastard daughter Aria's or leverage knowledge of her true parentage (1 success)
- Diplomacy DC 20 for declaration of neutrality in the conflict between Polding and the Duke (1 success)
- History DC 20 to stroke his ego about family's claims to the duchy of Bechaeux (1 success)
- Swear to help him against the Duke somehow (2 successes)
2. Well then, why do you want to find the white-eyed assassin? (requires 2 successes)
- Truthfully answer to learn of her dealings with the Beast (1 success)
- Promise not to tell the assassin that Polding sold her out (1 success)
- Be an elf or half-elf and claim familial bonds, the prejudiced Polding can't tell difference (1 success)
- Bluff DC 20 that they want for contract the assassin's services (2 successes)
Other questions that Lord Polding would pose include:
What makes you think the assassin will agree to what you want?
Many against one? Shouldn't I warn the assassin to even the odds?
I have a contract with the assassin...who fulfills it if you kill her?
If the assassin kills you, who inherits your holdings and fine magic items?
The example answers aren't meant to be comprehensive, but to provide inspiration and insight into the NPC's motives/personality and the intricacies of the negotiation's situation. What's good about using questions to organize the challenge is that it creates a back and forth between players and DM, and you can switch the order of the questions or insert filler role-playing between questions. I choose 1-3 successes per question (and 2 feels like the right number) because that way you can roleplay the NPC as initially being reluctant (0 successes), then being on the fence (1 success), then being convinced (2 successes) in regards to a question...which is a good indication to players of how successful they are without having to reference mechanics if you don't want to. Questions also help with pacing, moving things along so that the players don't spend all their time trying to convince the NPC of their trustworthiness or answering one question in exhaustive detail.