Also, I've been thinking about a Naruto/SFIII cross involving Oro myself a bit lately. One where Oro visits the Leaf about once a year to check on the seal that Yondaime trapped the Kyuubi with, because it was his design, decades and decades ago before he even became a hermit.
Naruto calls him "really really old man" as opposed to the Third Hokage, who's just "old man". Oro calls the Third "Brat" or "Young punk". Sarutobi, meanwhile, just takes the abuse because Oro is/was a figure of legend decades before Sarutobi was even born, although these days it's not clear why.
Anyway the payoff is that on Oro's last visit to the Leaf, several months before Naruto graduates, Oro and the Third are talking alone. For some reason, the subject is aging, and Oro makes a comment that he can guarantee Sarutobi a year. Sarutobi, looking underneath the underneath, (correctly) interprets this to mean he (Sarutobi) will be dead in a year, but he doesn't give a cause because he doesn't know one. Oro doesn't confirm it, but he doesn't deny it either. He just starts talking about "debts decades overdue", which Sarutobi does not understand. Oro doesn't elaborate, but presses his hand to Sarutobi's chest and chants a few words. Nothing happens. Oro says something to the effect of "you'll get it when you need it".
Exactly a year later, when Sarutobi is struggling against Orochimaru, Oro's gift reveals itself: it's enough of Oro's (the hermit's) mystical power to grant Sarutobi enough strength to pull Orochimaru's spirit arms off completely -- meaning that no matter what body Orochimaru is in, he can never use any ninjutsu again, because the arms of his very essence have simply been ripped off at the shoulder. Sarutobi thought to do this because he was struggling for too long to pull out Orochimaru's soul. Sarutobo then dies, Oro's gift expiring.
Oro finds out later what Sarutobi did, and decides the "brat" was a stupid punk after all, because his gift was meant for Sarutobi to have enough power to kill Orochimaru directly -- that was the debt. The debt Sarutobi owes the entire world, because Orochimaru's continued existence was Sarutobi's fault, his huge mistake, if you will.