Laen has designed a 16 magnet rotor to work with the original PCB stator. He designed it in Fusion360 and cut it out on his laser in an afternoon.
The initial order of mechanical parts has arrived from McMaster-Carr. Gluing the magnets into place and attaching the rotor to a shaft is easy, but I only bought 2-foot shafts, so its a bit unwieldy for a lab bench setup. I am working on a 3D printed structure to hold the stator in place above the rotor. When that is done, I can do some initial tests of performance by turning the shaft by hand and measuring the resulting voltage across a known load.