Sorry you're having so much trouble with shampoos Indecisive! They normally do travel minis of them, if you like them after that try ebay?
Have you tried Organix? I think the name is something else now but it's the argan/coconut/macadamia etc range. Did you try Faith In Nature or dead sea stuff?
Trying to think of sls-free stuff. Organic Surge? The L'Oreal sls-free one?