Okay, here's a few ideas I had:
Halfling Necromancer
I've been wanting to do this for ages.

A halfling, originally from Talenta, but given an education in Sharn. In the process, he fell in with the Cult of Vol, but never became involved enough to actually learn any of their secrets. Instead, he studies Necromancy for its ties between blood, positive/negative energies, and life. He's now adventuring to learn more about various magics and species on the planet, collecting skulls as part of his practice (and as a hobby). He refuses to create undead, seeing them as a mockery of the living (one reason he never made it far in the cult), but is quite happy to study any undead/deathless he comes across.
Classwise, he'd be a Wizard (Necromancer) who eventually takes the Loremaster PrC, and possibly Archmage if the campaign went high enough.
Shifter Psychic Warrior
This one's a bit tricky. This shifter grew up among a small band of Kalashtar, who taught him some of their skills. They taught him to take advantage of his natural claws when shifting, enhancing them with psychic powers. He adventures now to gain experience in combat, and acting as a watchman for any Inspired activity on Khorvaire.
I'd run him as a straight-up PsyWar, focusing on claw enhancing abilities. Unfortunately, he can only shift once a day to start out, which means he'll be relying on a sword for most battles until he picks up more shifter feats. It'll be a tricky balance, but given the chance to shift and manifest certain powers, he'd be able to deal a few nasty attacks each day, while remaining a good second-teir warrior the rest of the time.
Elf Monk
A member of House Thuriani, this elf grew up in the home of a nobleman. He was brough up as a companion and protector for this noble, to always be at his side. As the war drew to a close, the noble was tasked with attending the meetings as the Treaty of Thronehold was drawn up. On their journey, however, they were ambushed by bandits. The defenders were slaughtered, the noble killed, and our monk was taken prisoner with a few others. He was tortured, forced to watch as some of his friends died, and was only able to escape when a rival raiding party of bandits struck the camp.
He was publicly shamed for allowing the noble to die, failing in his one duty in life. However, some evidence was unearthed that the 'bandits' were not entirely acting on their own. And, sometime between his escape and arriving home, the monk had manifested a Least Dragonmark of Shadow. Thus, the House sent him away to Sharn, where he would be called upon when needed. Which likely would be whenever they simply needed a disposable resource...
He now lives as a wandering warrior, seeking nothing but to improve his own skills in battle.
I would play him as an LN Monk, working towards the Whirling Steel Strike feat. He's played similar to a ronin, knowing he has lost the favor of his House and, worse, failed to protect someone important to him. Hopefully he'd lead to some good roleplaying, the classic "finding purpose in your friends" story.
Human Cleric of the Dragon Below
He was raised in a small community, devastated by the war. When not struggling to surive, he only had some old books for his companion: legends, stories and teachings from a branch of the Dragon Below Cult. His grandparents had been members, but his parents had left those teachings behind in favor of the Soverign Host.
Yet, the Host had done nothing for his community. Disease, hunger and murder had been a way of life. In these unusual stories, he found an answer: Perhaps the common belief was wrong.
Khyber had been the protector and
Siberys the aggressor. Mortals had maligned the wrong being, who was now trapped inside the body of Eberron with evil things festering in the wounds.
He eventually left home, and found others who worshipped Khyber. Many were insane, or twisted to evil purposes, which only furthered his belief that the true story of Khyber had been corrupted by mortals who did not understand the Truth.
The character is a CG Cleric of the Dragon Below, following his own interpretation of worship of Khyber. He strives to help others, believing that many have been misled by the popular stories. However, he knows many would simply lynch him for his heretical beliefs, so he often poses as a wandering mystic. He encourages those who will listen to question the popular beliefs, while striving to cut the cancer of Aberrations from the world-body.
Just think of your favorite conspiracy-theorist, and supplant aliens/ghosts/pan-dimensional-beings for Khyber and you've got him. He means well, and his faith is true... he's just a little 'off'.
