The thing for me is (totally ignoring the tempting of Fate posed by several earlier posts. Aunt Keitaro was enough, thank you very much ) that Naruto would likely want to keep it a secret if he ever did discover for a fact that he's the Fourths son. At least at first. After all, it seems to me that his biggest desire is to be acknowledged for being himself. Being hated for the Demon, or loved because of who his father was, rather than what he's done himself; would just be wrong.
Course that could work into a story like this, Naruto's pedigree comes out into the open, everyone's running about like chickens with their heads cut off. Council members and elite clans rushing about trying to profit from the situation, and poor Naruto being upset cause he's being acknowledged, but it still isn't for anything he's done himself.
Hopefully this is makin sense; I nearly cut off a finger today and am on lotsa pain killers after gettin the stitches put in.