Not sure if anyone suggested this, or possibly they have in the past, but....

What about the ability to layer avatar items over each other to achieve certain looks. Like say two sets of back items that would work with the avatar's outfit. Or say head items and or outfits that would give an avatar a unique look resulting from the outcome of the combination. A basic over all ability to layer more than one item upon an avatar. Again, mind you just a suggestion to get some creative juices flowing.