off the top of my head:
South African who broke 4 min in the mile, but couldn't compete internationally because SA was banned for practicing apartheid (and he got the double jeopardy on that one). Went to Villanova, claimed to run his morning runs in about 4:30 pace, ran about 100 mile per week with no run longer than 12 miles (that from Running With the Champions, or whatever it is called, by Michael Sandrock). Ran just a little off the then-WR in the 5k (13:01) and the AR in the 1500m (3:29.77). COached by, I think, the guy who is currently coaching @ Haverford College.