This idea actually sprang from a thread that got started recently. But its more of a ripoff of the game 'arcanum'.
Mad wizard (arent they all) plots world domination via his enforced breeding project of giants and humans, making a halfgiant that is more obediant and brighter than a giant, and less morally encumbered than a human. Also, obviously I guess, much stronger than the average human.
I didnt really flesh the idea out any further than that, but it might be good for a single, one day quest, to find the lair, stop the halfgiant horde and the wizard.