I'm writing a blog called GuitarExtended to share my experience in using Pd as a real-time multi-effects for the electric guitar. I have built a foot controller based on an Arduino board, and everything is documented on my blog.
The "targetted" public are Pd users interested in extending the sound of their instrument (I am a guitarist, but it could be easily applied to many other instruments), as well as musicians with little or no knowledge of Pd.
Please feel free to leave a comment, or submit a patch that would be interesting as a guitar effect.
The blog is here : http://guitarextended.wordpress.com