Who knows some good monsters that I can repurpose as high-level orcs?

[Tourq]

My group is about to enter the orc town of Urglin, and I'd like some high-level orcs to give them a challenge. I'm thinking of brute and skirmish warriors, as well as a couple of shamans, and they all are a mix of levels 7-15. Orcs (by themselves) don't stand a chance as presented, so I'd like to use a few monsters whose stats and abilities I can substitute. I've already considered iconic characters. Any ideas?

Thanks for the help!

[Peachbottom]

Why don't you just give the orcs class levels? Fighter or barbarian levels for brutes and druid or oracle or witch levels for a shaman.

[Malwing]

Use the NPC Codex. Use the stats, call them something else, add +2 strength.

[TriOmegaZero]

You could look up the 3.5 book Monsters of Norrath. It has stats for CR15 orcs and CR20 kobolds.

[Undone]

Demi Orcs.

[Mathius]

Orcs are not that tough on their own. Let them have an encounter or two with stock orcs. They will mow through them but so what. For the tougher ones just add class levels.

http://www.d20pfsrd.com/bestiary/unique-monsters/cr-9/high-priest-of-orcus
http://www.d20pfsrd.com/bestiary/unique-monsters/cr-10/ury-sevenskulls
http://www.d20pfsrd.com/bestiary/unique-monsters/cr-7/deadwatcher-orc
http://www.d20pfsrd.com/bestiary/npc-s/npc-9/Krun-Thuul

This is what I found on d20pfsrd.