Eric Chavez wanted to play for the U.S. in the WBC, but didn't make the final cut. Now he says he would like to play for Mexico and says he qualifies because his father was born there.
Of course, Chavez told ESPN not to put an accent mark in his name as they do for other players with Spanish surnames and he also has told people to pronounce his name "cha-VEZZ" instead of "CHA-ves". (If that's unclear, he wants an English pronunciation of Chavez.)
But if Mike Piazza can be Italian and Dan Haren can be Dutch...
If they used great-grandparents, I could play for the Austro-Hungarian Empire team.