In order to get a better idea of the mechanisms involved, I ordered and assembled a MeArm. I must say, for the price it's unbelievable! Here are a couple of photos.
There are a few improvements I'd make. One, I wouldn't try supporting the entire mass of the arm a tiny 9g servo. I would try to support it on a bearing plate, or thrust washer or something similar. It can even be a piece of plastic. Two, actually there is no two! It works well!
In order to start designing mine, I have begun to use the above 2D-lasercut parts as a "baseline" for my own arm. I used to use Solidworks but now I'm trying to keep it all open-source including the design. Thus, OpenSCAD. I have posted the beginning of my SCAD code here:
which will let you parametrically design any of the support arms above, in 2D. You can then export a DXF for cutting directly.