The best player I have seen out of an obscure nation would be this chap -
http://i279.photobucket.com/albums/k...l_Houghton.jpg
He was discovered by Leeds when he was 19, I signed him 1 year later for 60k after my scouts thought he would turn out half decent, and after a couple of loan seasons in Spain his attributes shot up drastically. He was ready to make his debut in my first team when he returned, at which point my chairman thought it wise to accept a £2.4 million offer from Chelsea for him. Which I was understandably unhappy about...
So some of them do make it in the big leagues, they just need to be found first. I've tried signing a couple of newgens from little places like Belize/Montressat since then, but most fail to get a work permit and retire. Unfortunate really, since a few had fairly good PA's.