Aus_Snow said:
Um. So what was the other part?

I have to know, now.
It only works if your GM allows a Wizard familiar that gives +3 Diplomacy (perhaps a Mink. It isn't on the list, but it doesn't seem unreasonable). Otherwise, you are stuck with +32.
Here goes:
Half-Elf Telepath1/Warlock1/Wizard1. Int 14 and Cha 18. Other stats don't matter.
Skills:
Level 1: 4 ranks in Diplomacy, Sense Motive, Bluff, Knowledge: Nobility and Royalty (all class skills)
Level 2: 1 rank in Sense Motive and Bluff (class skill) and a rank in Diplomacy (costs 2, cross-class)
Level 3: 1 rank in Knowledge: Nobility and Royalty (class skill) 1 rank in Diplomacy (costs 2, cross-class), 1 rank in something else
Feats: Diplomacy and Negotiator.
Psion Bonus Feat: Psicrystal Affinity [Friendly]
Warlock Invocation: Beguiling Influence
Familiar: Mink (or any other +3 Diplomacy)
Bonus: +4 (Cha) +6 (ranks) +6 (synergy) +6 (Beguiling Influence) +3 (Psicrystal) +3 (Familiar) +3 (Skill Focus) +2 (Negotiator) +2 (half-elf) = +35!
(You can get +36 with that feat for half-elves from Races of Destiny that increases Synergy to +3 instead of +2--take it instead of Negotiator)