I've seen it Rocky, but i can't create to save my life (well, probably could but ther's no danger in sight xD).
There are alot of people on this board tho, who can, seeing Dennis Linds helmet thread. Plus, a unique, brilliant or cool design is always very subjective. Take me for an example, I like straight lines and flashy colors... someone else like it more subtile, with a lot of fine 3D effects, dry colors or whatever. The description you added is probably something to work with, but it doesn't trigger anything in me. Heck, the helmet I'll be using is a different colored version of the last one i've made; added personal stuff making this one unique.
I also totally dislike Tribals and therefor am totally wrong person for this job, since i can't even figure out what nice means in this context
However, i don't mean to be an arse, but Dennis gives out 100 pounds for just creating one and not also making it work on the lfs model. Don't get me wrong, but that could turn off potential designers, too.
Like Dennis did, you could provide an example.. just something to get a feel for your personal taste. The more info you give out the for satisfying it will be. (not only for you) It doesn't have to bean actual helmet but any graphics you like.
I hope this helps.
Good Luck.