As usual, I have several ideas that I'll shotgun out to try to narrow the focus a bit.
1) A celestial bloodline sorcerer who was raised in a convent or monastery most of her life and has thus been well educated, but also very sheltered. Circumstances have changed of late, compelling her to leave this protected enclave and venture out into the world. Perhaps there was some kind of attack, and it was deemed unsafe. Or perhaps it was even destroyed, with only the most fortunate of circumstances allowing her to survive. Or maybe there was simply a calling to go forth. I'll leave the specifics open for now. The character is unfailingly polite and almost ridiculously compassionate and just plain nice. Despite her upbringing she's not a zealot, nor particularly judgmental in a religious sense...though she has no truck with cruelty. She's delighted to actually see the things she's only read about on musty old scrolls, and tends to be annoyingly perky; prone to see the best in any situation, however grim. Probably a "summoner" sorceror, with secondary focus on buffs and utility.
2) Draconic bloodline sorcerer (possibly with draconic heritage feats or feats from Dragon Magic if you permit) who has been part of a traveling 'circus' of sorts, using magic to assist in the spectacles and of course moonlighting as The Astounding Snake Woman and various other monikers. Again, the reason for her leaving this environment is flexible, but I imagine it could easily just be a desire to accomplish something of consequence. This character is more troubled; oscillating between almost manic bouts of hauteur as she glories in her superhuman abilities and maudlin moments of depression as she wallows in her limitations. She has good basic values, but struggles sometimes to do the right thing against temptations of power, riches and knowledge about her favorite subject: dragons. I'm thinking this sorcerer would focus on personal augmentation/transformations, with some blasties as well.
3) Air elemental bloodline sorcerer; the product of an ancient noble line now fallen and scattered that consorted with djinn in days now long gone. This could be Shoanti, perhaps, representing a descendant of the old kingdoms that dotted this land before its colonization from outside. This character is a study in contrasts. Quite literally 'airy' and flaky, but who considers any sworn oath to be an unbreakable bond. Self-centered, but compelled to perform random acts of kindness. Resentful of these intruders to her people's lands, but disdainful of the Shoanti's slowness to adapt and unite. She loathes what has become of her people, but freely works with Varisians and others to try to understand their strengths...and weaknesses. In time I could see her choosing to try to bring the tribes of Shoanti together and forge them into a real power, perhaps eventually attempting to carve a Shoanti nation that can defend itself from these foreigners. This would be an "artillery" sorcerer, primarily.
Those are the main ones, though I have other ideas I can develop if none of those appeal.
Whaddya think, sirs?