Hey ADL, Brian emailed me a while back about this and all you gotta do, he said, is to extrude the edge a little bit that you want thicker, smooth once, check it out, and go back and extrude again if you need it thicker/sharper.

For Subd's, go into poly mode, extrude the edge, and go back to SubD mode, choose the SubD edge, and run a partial crease on it.

Hope that helps