Eh, I wouldn't like seeing gang specific skins, especially since those would be sold at all clothes shops and would still be available for anyone to use. We already have a system where if someone makes a sick skin or few, he can talk with managers about getting them implemented to the server.
Same is with graffitis, but obviously there is a limit to how much we can / will add to the server so the download for a first time player doesn't get too massive (people with 256 kbps internet is pretty common in VC:MP)