Aurora had 6 "Great Moments in Sport" figure/diorama kits, all issued in 1965. You remembered them pretty well: they were Willie Mays (1 figure), "Jimmy" Brown (3 figures), Johnny Unitas (3 figures), Dempsey vs. Firpo (3 figures), Jerry West (2 figures), and Babe Ruth (3 figures). According to my copy of Bill Bruegman's "Aurora History and Price Guide," they were a pretty resounding failure sales-wise, and were never reissued.
I thought they were pretty neat when I saw them in the book, because, though I seem to remember almost everything else Aurora ever produced, I don't remember ever seeing any of those (and I was 9 at the time, so I'm sure the trademark Aurora colorful box art would have made an impression).
I have no idea if they'd be available on e-bay, but the price guide gives (1992, pre-ebay) prices from 60-350 dollars unbuilt, 30-125 built up; I shudder to think what they'd go for these days.
Good luck and good hunting.