OMG Season, your ideas are the bomb! Here are some ideas I have:
Zookeeper.
His Pokemon are always Johto/Kanto starters + Pikachu, Girafarig, Luxio, Luxray, and Seviper.
Ancient Person.
He would be found in a place like Ruins of Alph, in a side plot where you somehow meet the makers of the ruins. His Pokemon would be Unown, Kabuto, Kabutops, Omanyte, Omastar, Tyrannitar, Relicanth, Natu, Xatu, Feebas, Sandshrew, Cubone, Cranidos, Sheildon.
Museum Keeper.
They would be in a Museum. They would have the following Pokemon: Slowking, Kabutops, Omastar, Aerodactyl, Espeon, Umbreon, Smeargle (:D You saw it coming didn't you?), Aron, Baltoy, Claydol, Duskull, Porygon-Z.
Star Gazer/ Astonomer.
You would only find them at night on their backs (They'd need a special sprite for that ;)) and they would only battle if you'd talk to them. Here is a sample script:
"Wow, Mars is big tonight, and Orion is easily visible. Huh? A battle? Ok, but make it quick."
After Battle...
"You can always see Orion because of the three stars"
"Wow, that star is cool! See it?"
After battle...
"No, not that one! That one!"
They would have the following Pokemon: Cleffa, Clefairy, Ampharos, Togepi, Togetic, Natu, Xatu, Umbreon, Teddiursa, Ursaring, Porygon, Porygon 2, Porygon-Z, Sableye, Lunatone, Castform. If only he could get Jirachi :D
I like this thread! Cool concept!