There are nice cheap Chinese switching power supplies can be found on AliExpress, like this one:
They are pretty common among hobbyists as power source in their project because they provide quite acceptable output power quality for low price.
One of the drawbacks of such powers supplies is their metal body, which has dangerously opened high voltage contacts.
This project provides ready to use parametrized 3D modelled case for this power supplies. It contains ready STL files for power supply sized approximately 90x60mm. Also, if you need other dimensions, you can adjust source 3D model in Autodesk Fusion 360.