See here the presentation David and I gave on the paper marbling machine the day before the final project due date!
This presentation does contain most of the relevant documentation. Beyond the content of the presentation, I would also add that we are very interested in what this machine can do, not just how best to build the machine.
We want to explore how similar or different two marblings created with exactly the same parameters may be. We are also in contact with a paper marbling master and several more casual marblers. From these people, we hope to learn more about the techniques used to create marblings and hopefully be able to reproduce these techniques or take a different, computational approach to the techniques.