http://www.shacknews.com/featuredarticle.x?id=1124
For the time being, this appears to be cosmetic only, with no changes to the game.
Shack: Will these items carry bonuses that impact gameplay?
Robin Walker: Right now they're all cosmetic only, but it's obviously more interesting if they become more than that, so we're still thinking about that. Shipping them without gameplay changes seems like a good way to tackle the first problem, which is to ensure we don't break our silhouette based class identification. It also starts us on another path that we're interested in, which is allowing players to have some control over their appearance.