If you're keen enough, you could try sculpt-building your own helmet from scratch from foam or latex. I've seen people do some amazing things costume-wise with foam and/or latex.

http://technabob.com/blog/wp-content...dragonborn.jpg
https://img0.etsystatic.com/033/1/64...82000_l49w.jpg
http://thedaoofdragonball.com/wp-con...ta-cosplay.jpg