You want the fit a Mac Mini nicly into a 19 Inch rack case? A half 19 inch rack mount for a MacMini fitting in one unit.
The idea came from a project for a live stream solo rack build around a Blackmagic Atem mini switcher. The build is 3U high. On one level is a Mac next to a Blackmagic Ultimate 12 Mini. But could be any of the BM Mini series devices such as Hyperdeck, Teranex, Web Presenter or UltraStudio.
Get your self a Blackmagic Teranex rack shelf and fit your Mac in. Installed it will need ⅔ of 1U in width due to the orientation of the Mac.
Technical remarks
There will be an on-button in the front of the panel. It needs a bit of force to break it free. The button is spring loaded but you have to move it for a while after printing.