I don't know much about the BukkitContrib plugin but isnt it meant to be able to add capes and skins to players with the client version of it. But back to my suggestion would it be possible to make it run texture packs on different worlds.
Nah really... Thats what BukkitContrib is. Its a plugin/client mods. Currently it doesnt have API for texture packs. Afforess might include API to work with texture packs later on...