I do not know of any tutorial out there floating around to accomplish this style. I also do not know of a plug-in. Here's the trick with this style of map...it's basically all lines defining the shape of the landmasses, then overloaded with text and a little color. I've always liked this style as well and I think what I'll do is make up my own tutorial for it (using Photoshop). Hang tight and I'll see if I can have it done within the week.