It might be nice to make them, try them out and post any alteratons etc...
So... here's one I found a while ago for a simple castile shampoo is made with:
4oz Castile Soap Flakes
950ml Water
Bring the water to a boil. Turn off the heat and pour water over the soap flakes. Stir until the soap flakes dissolve. Once the mixture has cooled, store it in a plastic bottle.
You may vary this recipe by adding essential oils to the shampoo. Lavender is very calming and makes a good addition to the shampoo. Peppermint and citrus are invigorating. Experiment with different oils to find the ones you like best. If you wish to add essential oils to your shampoo, mix 4 to 8 drops of the oil in a teaspoon of rubbing alcohol. Stir it into the soap mixture just after all the soap has dissolved.
You may also use this recipe to make an herbal shampoo. Instead of plain water, make an herbal infusion. Use one-half ounce of dried herbs for each quart of hot water. Let the herbs steep for at least 20 minutes. Reheat the infusion if necessary, pour the hot infusion over the soap flakes, and stir well.
I'm thinking of these scents:
Rosemary
Lavender and Lemon
... I just have to search out Castille Soap Flakes or bars

Ginger and Grapefruit Liquid Soap
500g finely grated good quality castile soap
500ml distilled water
10ml glycerine 5ml vodka
5ml ginger EO 10ml grapefruit EO
Put grated soap and water in double boiler and melt slowly on low heat. remove from heat add glycerine and
vodka. leave to cool for a few minutes then stir in essential oils. pop into bottles and bobs your uncle you have yummy smelling liquid soap. You can use it as soon as it's cooled and bottled
I simply cannot wait to try this one...