Shadizar has The Professional.
Messantia has Merchant Prince, House Agent, Agent of the Crown.
Aquilonia, Flower of the West has Gunderland Mercenary, Gunderland Pikeman, Poitainian Knight.
And, so forth.
I don't think there's a single prestige class that I've seen in any of the books that I'd want to play. If you come from a background where you learned to hate prestige classes, then this is probably something to be enthusiastic about. For me, I'd rather that instead of coming up with new classes with such limited usefulness that there was simply advice on how to advance characters to fill these specialized roles.