I now want to add cams, so these objects move in more complex patterns than
just around in circles. Not as complex as automatons, but leading in that
direction.

Go to http://www.arthurganson.com/ and buy his DVD. You will see
tons of ideas on how to arrange linkages, etc. Most are brazed from
wire. Fascinating stuff, and incidentally, a great way to keep
visiting
nephews rivetted to the couch and out of trouble...
--Glenn Lyford