I came across Sabun Living while I was looking for alternatives to my fav beer shampoo (I can't find the all natural Beauty and the Bees series in Spore anymore).
They have a recipe in their kitchen recipes on how to make your own beer shampoo:
Beer contains proteins that coat the hair shaft, building up body and helping damage repair.
a) 60ml unscented shampoo base
b) 40ml beer (any cheapo brand)
a) Bring beer to a boil in a saucepot.
b) Remove from heat and add in shampoo base, stirring in gently to avoid foaming.
c) Ready to use once cooled.
This looks really easy, and you can get the shampoo base from their online store. Ooooohhh, I'm really tempted, especially since Sabun is a Singapore-based store!