I didn't want to go back to shampoo though. That would have been a huge step backwards and I wasn't willing to just give up like that.
So, I headed to the Food Conspiracy Co-op and bought a bottle of "shampoo." It's Uncle Harry's Hair and Body. The ingredients are few and simple: Castile soap, apple cider vinegar and hemp oil (some can contain other ingredients like lavender essential oils, but nothing harmful).
The cool thing about a shampoo like this is that, unlike commercial brands with harsh ingredients, this could actually be made at home. Large bottles of Castile soap and apple cider vinegar can be purchased relatively cheaply, and hemp oil is available at health food stores and online. If one really felt energetic, even the Castile soap could be homemade.
At the moment, I'm being lazy and just using good ol' Uncle Harry's. Perhaps when I'm done painting walls and scraping/staining floors and moving, I'll give it a go. Maybe.
Been using the shampoo a few weeks now. It produces suds (which I know is super important to some people), doesn't have a harsh smell, and makes hair feel wonderfully soft and healthy. I do follow it with a rinse of 2 Tablespoons apple cider vinegar with 2 cups of water (I just use the water from the shower so it's not a cold shock), but I skipped that one day and the shampoo was fine on its own. My hair gets a wash twice a week.
I will say, since I started this whole thing, back with the baking soda/vinegar, I have not had a single split end. Given that my thin hair is rather prone to them (a few months after a cut my hair usually looks like it was run through a lawn mower), and compounded by living in a very dry desert, that is proof enough for me that giving up the 'poo was the right way to go.