Warhammer Online's new appearance system in patch 1.3.6, and it's a significant upgrade to the game's setup. Designer Sean Bosshardt has penned a developer diary explaining how the new appearance system works in practice, which essentially gives your equipment its own set of equipment.
The short version is that when looking at your character's equipment, you can flip over to their appearance slots, and then each eligible item can have another item placed within the appearance slot. However, the new appearance doesn't consume or use the item which granted the new look, and it stays with that piece of armor -- so you can change the look of a pair of shoulders, and that look stays with them until you change it again. It's an interesting system with several nuances, so Warhammer Online players are encouraged to read the full diary to see just how nice they'll be looking when the new patch hits.