OK, I'll try.
(In the example, PC:s are male and the NPC is female. A bit of nomenclature I stole somewhere.)
Appropriate skills:
Diplomacy
Insight
Religion
Arcana
Unlockable skills:
Nature
Intimidate
Forbidden skill:
Perception (heh)
Something diplomacy-ish, certainly. Maybe the PC:s are seeking help from a bishop of Wee Jas (insert your setting's god of magic here) before an excursion into the wilderness.
Diplomacy: The PC puts forth reasonable arguments for the bishop to render aid to them. The first success has the bishop reply wanting to know about the PC:s qualifications in detail, unlocking Nature.
Nature: The PC impresses the bishop with his survival skills and convinces her that the group is likely to succeed in their endeavour.
Insight: The PC gets a reading of the bishop's general attitude. The first success gives the hint that the bishop dislikes nosy people (discouraging Perception checks). The second one might give the whole list of appropriate skills (which shouldn't be hard to figure out, but I doubt hard facts will be unappreciated). Then it's time to hint that the Insight skill is "worn out".
Religion: One success gives the PC information that the bishop is in fact supposed to give aid in this case, according to ancient scripture detailing the duties of the church of Wee Jas yadayada. This unlocks the Intimidate skill.
In general, the PC discusses religion with the bishop, warming her to the group. The PC gets +2 to further diplomacy checks.
Intimidate: The PC lays the religious smackdown on the bishop, reminding her about the supposed punishment for going against Scripture (eternal damnation etc). I'd consider making this a hard check which automatically wins the conflict on a success but gives two failures on a failed roll.
Arcana: The PC discusses magic with the bishop, impressing her with his magical knowledge. That specific PC gets +2 to further diplomacy checks.
Perception: The bishop spots the PC peering around the room and gets upset at the nosy lout. Automatic failure.
OK, so Perception as automatic fail feels a little forced, but in general, this seems like a nice source of inspiration if you allow yourself to deviate from the guidelines. I'd take out the forbidden skill if I used this encounter.
