Donovan? Can't think of many others.
Tim Howard, Clint Dempsey, Brad Guzan, Jozy Altidore, Carlos Bocanegra, Brian McBride, DaMarcus Beasley, DeAndre Yedlin, Eddie Johnson all would have played in the premier league I believe.
There's quite a few in Germany now IIRC.
I'd say there's probably more Americans in Europe than Australians atm.