Magic-related Organizations for a RotR campaign?

[Ron Hay]

One idea I have for my soon-to-be-run Rise of the Runelords campaign is that all of the characters come to Sandpoint to help setup/re-establish some sort of mage tower. This would have all the characters associated with some organization that would want such a tower in Sandpoint. Most would be spell-slingers of some sort, but there's also the option of warriors to protect them, rogue-types to deal with people, clerics of faiths friendly to mages, etc.

Unfortunately I'm a total newb to Golarion, so I look to you guys - any suggestions for organizations that would fit?

[Xen]

I am just wrapping up Burnt Offerings, but I have read the whole adventure path, and I think this would be a great fit. I think that it would require at least one "diplomat" because I got the feel that Sandpoint is a more down to earth, close-nit community. So outsiders showing up and saying "Hey, let's build a mage tower!" might take some persuasion, but totally feasible and awesome way to give the PCs extra motivation to help the town. I would put more emphasis on the Thassilon magic, as it will tie directly with their personal goal.

For organizations, I'm really not 100% sure since I'm pretty new to Golarion as well. But honestly, you wouldn't need it. You could just have it as a joint business venture that they decided on in Magnimar or Korvosa.

[Movin]

The Geb, Nex, and Cheliax factions might work. I doubt the people of Sandpoint would be horribly interested in rotted corpses, devil summoning or arcane horrors. This would be why all the factions would use dummy organizations to prevent that from being realized. Or in the case of RoTRL well intentioned cadets and neophytes adventures that all just happen to be level one.
Lots of room for political drama in this, sounds like a fun time.

[Old Drake]

How about Karzoug himself being their employer?
He's rebuilding his power base, and is very biased towards human, so forming a human magical society would fit. So the players would play a critical part in creating an espionage and lobbying ring for their main enemy and give them an additional reward when they defeat him (leadership of a network of mage towers). Of course they won't learn who really employs them until near the end.