It's a pity i haven't got time to work for a campaign but, just have a look in war3's mpq UI folder, there lie all the graphics for the whole interface, in different folders.
And you'll find all the control files in this folder :
UI\FrameDef
and its subfolders...
I suggest you open one of the .fdf files with notepad.... for the revelation ^^
The trick is that NRM is a mod, meaning (I'm pretty sure) that it's a war3.mpq download to play it. That's entirely more flexible and more huge than implanting files into a map.
The same they did in RoK. The skinning is easy. Replacing the 3D stuff with another existing one is also easy. Creating a new one is hard (for me impossible).