http://en.wikipedia.org/wiki/Isidro_Sánchez_Macip lol 1 cap like 4 years ago in an U-23 team that failed to qualify to the Olympics, that was time well spent...
Hay un mexicano naturalizado salvadoreño que estuvo en varias concentraciones con la actual selección salvadoreña, pero no sé si jugó algún partido con ellos. PD: Se llama Arturo Albarrán.
You meant that they're American by birth, right? Martin Vazquey is the obvious one. There are several Mexican born youth players that reside in the U.S. that have the possibility of naturalizing at some point. And just about any U.S./Mexico dual national with a pulse is getting capped by team USA.
No, Mexican by birth as well. According to constitution of Mexico, persons born abroad to at least one parent who is a Mexican citizen are also citizens by birth.