As I understand it, no single individual has the power to strip any of them (priest, bishop, or otherwise) of their "title" - that can only be done by the house of bishops or general convention. However, he is effectively unable to practice as a priest or Bishop in the US due to his being deposed, so he might as well NOT be one. And most of the priests--who are not a part of churches creating the schism--I know consider the Archbishop to be an ass with no balls (see Nigeria), so his opinion isn't exactly worth much in the US.

One of my best friends is a priest in the Pittsburg diocese, and holy cow did Duncan make a mess out of things.

From what I know of the facts, the man should be in jail.

If you're really and truly interested in the whole "canon-law" of it all, I can ask one of my many priest friends (what happens when you tie your wagon to one--you get to know many many many more than you ever thought you would)...or my girlfriend (who is also a priest).