Thanks.

Someone recommended Steve Kaufmann before in this forum. His Chinese is super good.

I did a search on Alexander Arguelles and found a lecture series by him. What interested me is that he says that the more compliments you get on your accent, the more it shows your foreign accent exists, for if you are really as good as the natives, people won't notice it. And he also says that he, as such a worldly renowned lingustist, and with the living and teaching experiences that he has, has never physically met one single person who started learning a foreign language after early age speaks that language without any (foreign) accent. 

Here are the links to his "Accent Formation in Foreign Languages" series: 

part 1: http://www.youtube.com/watch?v=bz7RB-QQFVw
part 2: http://www.youtube.com/watch?v=wkfDe8uUFw0
part 3: http://www.youtube.com/watch?v=wRFmuSeKzKk
part 4: http://www.youtube.com/watch?v=7HzXT7daOnQ