Dark Helmet, the only one out there seems to be incomplete.
I wouldn't use the other Dark Helmet that got posted. It isn't really accurate and it is very simple. I made one you can use. I would love to see pictures of it if you decide to build it.
Here you go:
https://skydrive.live.com/redir.asp...209EBD4D8A434F!288&parid=21209EBD4D8A434F!287
Just please give me credit for the file if you post your progress in any costume/prop threads. Thanks.