Flayed, Mustaine, Waffle and a few others had maps in the works a while back. I started one, but don't have the patience to finish it. Nhawk is working on it now. Its in the Terrain Editor forum.
I'd like to see a bunch of new maps as well.
I give alot of credit and thanks to all the guys that have and are making maps, skins, and sounds to make this game even more enjoyable for the rest of us.