By Bosnian origin i mean Croats from Bosnia and Herzegovina. I know you know this, but not to have any misunderstandings, Croats, Serbs and Bosnian Muslims live in Bosnia. Those Bosnians who play for Croatia are Croats from Bosnia (not Bosnian Muslims or Serbs).
Corluka and Petric are Croats born in Bosnia.
Ivan Klasnic, Niko and Robert Kovac are Bosnian Croats but they are born in Germany.
Simunic is a Bosnian Croat but born in Australia.
Rakitic is a Bosnian Croat born in Switzerland.
As you can see, those from the western countries are mostly the Croats from Bosnia and Herzegovina.
Also you can find theese kind od examples in Serbian NT, however I don't blame players, I blame our country, FA and politics. It's frustating sometimes to see some of the best players playing for other nations, but we hardly can do anything and that is most annoying thing.
Theese things aren't only in football and we can took an example of Croatian tennis player Cilic who at the beginning was talented Bosnian, but Croatia gave him everything and made him player that he is now, and I'm 100% sure that wouldn't be nowhere good as he is now if he continued to play under Bosnian flag.
To sum things up, Croatia and Serbia have good scouting system, more prestige than Bosnia and most important thing money to invest into sports and that is maybe the biggest reason why some players are choosing other countries instead of us (Bosnia).