http://www.texturepacker.net/ seems like an option if we want a new customizer. It has a starter pack function so theoretically we could have all the textures hosted there and have alternate textures as well. Just an idea.
Maybe you could try out another resource pack custumizer: The painterly pack. It's one of the best costumizers out there. Try it here: http://painterlypack.net/customizer.php