Shampoo base not available?

I can add essential oils to a shampoo base, but where to get the shampoo base? The natural kind, like that somone would make at home. I'm looking for just like homemade, not with "Cocamidopropyl Betaine" or other artifical ingredients. the two sources http://www.mountainroseherbs.com
or http://www.wildroots.com don't have anything like that...maybe they stopped carrying it?