Many modular systems rely on the DAP MP-1 Master Panel 19" 2U, which I didn't have available, so I made a printable version.
The two pieces can be printed on 256x256 bed and glued and/or screwed together. It provides 10U horizontal split allowing you to use a wide range of module. The pictures depicts a blank U, a 2U fan module and a 1U RaspberryPi module.
Other modules are available on my profile.
The author marked this model as their own original creation.