So the idea of going modular came up, and it just makes sense.
At the design meeting we decided to make a paint head that was versatile enough to be mounted on either a 3D arm or an XY Table. Why stop with the customization there? The new concept is to give the paint head a configurable set of mark making tools from which it can operate. We are having another design meeting this weekend to go into the particulars. This picture though shows a rough first conceptualization of a nine module system.
Oh... also in keeping with the open source nature of this project, here are the google sketch-up documents to go along with this mock-up. We plan on sharing everything so anyone can follow along and contribute.