I think it would be real cool if you can make one that looks like a "hunter" if you don't mind being a bad guy.
Making one of the Master Chief would be interesting. I'm thinking if you can make some kind of framework, then use lots of mylar wrapping painted in your favorite color, it might work but then again, it might come out odd looking.
If you do figure out a good way, I'd love to see a pic!
Jay