If you haven't found him already, you might like Wintergatan. Martin Molin of Wintergatan is currently in the process of designing and building a successor to a marble machine instrument he built a few years ago and is extensively documenting the process through YouTube. He doesn't shy away from showing mistakes either and all of his videos are beautifully shot and scored (often with music by him). If you are interested in engineering of any kind, I would highly recommend watching the Marble Machine X series from the start. He learns (and thus teaches) a lot of valuable lessons in the process and it is really satisfying to see it all finally coming together.