How exactly is it going to work? Will you only be able to make a skin for multiplayer? Or will it be kinda similar to the map editor, where you get a randomly generated ID to use your skin on a map you're creating?
Those are my main questions/concerns for now, might add a few as more information is given.
I guess this thread could also be used as some sort of skin editor discussion mega thread since I haven't seen anyone else create a topic.