I needed longer Duplo compatible bricks, so I imported the 2x4 model file from the original author into Autodesk Fusion 360 and split and rearranged the body to create all the other length variants. I checked my method against the authors 2x8 brick and it matched the length perfectly. Original: https://www.printables.com/model/83583
The 2x18 is the longest my Prusa i3 MK3S+ can print. You need to rotate it by 50° on the print bed, remove the skirt and it will barely fit. Make sure that none of the inner rings break loose during printing.
A note about the image: I was too lazy to peel out the brims from within the rings, but you can remove them easily.
Printed with these settings:
The author remixed this model.