Been reading this book "Heroes of WWII" and there was a Fort called Fort du Roule in Cherbourg that I thought make an interesting map, especially defensively. Here's a passage from the book.
"...fort du roule, the strongest of cherbourg's defensive positions. A multilevel fort built into the face of a promontory(
http://en.wikipedia.org/wiki/Promontory), the structure had mortars and machine guns in concrete pillboxes spaced across its face. Additional bunkers fronted with barbed wire-filled antitank ditches, guarded the fort's approach."
sounds a bit much i dont know if it can be made in CoH but it sounds like fun
