The base and dome are not printed, but both are of simple construction.
The dome is made from 2 layers of 3mm ply bent over 2 arch frames, 1 at a time with glue inbetween the layers. On top of the ply was a layer of 1/4 dense foam sheet with self adhesive on 1 side and we chose to go with a chestnut leather with polished brass handles and connection plate. The base is made of 12mm ply.
The electronics are simple, 2 x PWM speed controllers, you can pick up on ebay for about $10 a piece, 2 x 10k potentiometers to control the speed of both motors and a 5A 12V power supply. The potentiometers are mounted on a small black project box connected to the machine via a few meters of 5 core cable.
See PDF for notes on additional items required, hardware, motors,bolts etc...
Additionally you will need a thin sheet of either tin or perspex for the toy plate, I used some 1.2mm tin I had lying around.
Please leave comments for improvements or ideas on what or how I can improve something, or if you build one, please post a pic (keeping it PG).
The toy mount included in this design will fit silicone or rubber attachments from MotorBunny, Sybian, or Cowgirl. Just for fun, this will also work with the Vac-U-Lock adapter I have drawn up (https://www.thingiverse.com/thing:3555996).
The control box is a seperate "thing" here https://www.thingiverse.com/thing:3562714.