I know this reply is a little late but here are my thoughts on the matter.
I, personally, would buy some kind of moisture-rich bath and shower bar (I currently use Zum Bar, Honeybee Gardens bars, and Dr. Bronner's liquid soap) if it was of a high quality. I would not use a shampoo bar for a variety of reasons (I currently use ShiKai and Aubrey Organics and Aveda). However, I do know that they are popular in the natural body care world and would probably find an audience here.