Most of the American soccer pairings I thought of actually did have overlap. But I'll go with Lalas and Bocanegra on the US National Team... I think they would've been a formidable backline duo.
Football - Dan Marino and Ricky Williams... Ricky would've been the missing piece of the puzzle, and the Fins probably would've won 1-2 Super Bowls with that combination. Sadly, Ricky didn't come to the team until 7 years after Dan retired.