Hi. I don't know if you've found a recipe yet, but you're welcome to try this one. I can't remember the website I found it on but it sounds like it might work. Ingredients: 1 lb opaque MP base, 1 teaspoon almond oil, 4 teaspoons shea butter, 1 1/2 teaspoons castor oil, 1 oz beeswax, 1 1/2 oz cocoa butter, 9 drops EO or FO, colorant is optional. Directions: Melt oils/butters & beeswax separate from MP base. When both are melted, combine & stir constantly until cooled. Add fragrance & color if using. Pour into mold & cool. Cut & package as desired. Hope this helps!
I just watched a you tube about honey beer shampoo bar. They used 1 lb. honey MP melted then added 2 Tbl. beer and 1 tsp. shea butter. I thought it was interesting. I would sure use Bramble Berry's honey MP though. I got some MP from another company and it stinks next to Bramble Berry's quality.
Some melt and pour bases are made with synthetic detergents, but nowadays it's easy to find a soap base made with lye (sodium hydroxide) same as any other soap. One line of melt and pour shampoo bars that come to mind, is called Bobeam. Pronounced Bo-be-um. Here is the website: