Interesting, and it feels vaguely BECMI-ish for some reason. I don't have my books, but wasn't there some sort of "destiny" mechanic in BECMI, perhaps at Companion level? I recall one could become a "paragon" of one's class. I also recall the "polymath", a destiny for jack-of-all-trades types. All that might just be vague misremembered recollection, but perhaps this notion of Polymath notion might make a nice counterpoint to your Nonpareil.
The mechanics you're talking about are the Paths to Immortality. You find them in the Master Set; they're the forerunner to 4E's Epic Destinies. The paragon paths I was thinking of are more in the Companion line.
As a Paragon, your goal is to establish yourself as the supreme master of your craft; among other things, you have to find, challenge, and defeat all rivals within a defined radius.
As a Polymath, your goal is to become a master of every skill. You have to reincarnate as a member of each class in turn, starting at 1st level, and level yourself all the way up to 36 in every single one.
There was also the Dynast, which requires you to found a dynasty and maintain it over centuries (time travel was a requirement IIRC). I don't remember offhand what the last path to immortality was, will have to check when I get home. Something about achieving some great heroic deed, I think.
I think these are good to look at as inspirations for a third-tier campaign, but they suffer from some major problems--chiefly the fact that they're about as unsuited to party play as you can possibly imagine. The Paragon is off battling rivals and shouting about how there can be only one, the Dynast is bopping around time like a medieval Doctor Who, and the Polymath is busy killing goblins and dreaming of name level for the third time. Kind of hard to get the three of them into one gang...