Tobirama Senju vs Seven Ninja Swordsmen of the Mist (the previous generation, with Zabuza in it). This would be interesting because we'd finally learn about his abilities, and he'd probably be forced to use his S/T jutsu at a few points during the battle. However, I don't see him being forced to use Edo Tensei.
Prime Hiruzen vs Sandaime Raikage. Hiruzen doesn't have wind, so how can he beat the Sandaime Raikage? But he's "The Professor", remember? He'd find a way.
Nawaki Senju vs Konohamaru Sarutobi vs Fresh-12-year-old-genin Naruto. Restrictions on Naruto = 2 Kage Bunshin. They were all around the same age, and they all want(ed) to be Hokage, so who really had the power to back it up (between the three; they (are) were all considerably weak).
