This is the project I started during Christmas holiday season, so for now it is not in its greatest shape, but it at least looks like a rack.

I wanted to have a 10 inch rack that will be cheap, modular and easily expandable, so the requirements were:

1. Ability to both incorporate some existing things you can buy like aluminum extrusions or mountable gear and to fully 3D print everything
2. Modularity - both an ability to create and combine several "rack modules" and ability to combine any gear that fits 10 inch rack inside of the module
3. Customization - one should be able to change rack width, height or depth with a minimal amount of changes to other components

So here it is - 3 modules ("power delivery" at the bottom, "compute" in the middle and "network" at the top) - they have the same core, but using different enclosure options:

Since it's deeply WIP and I just got it into one piece yesterday to test the setup, cable management is still ugly, but if you were using mini PCs with external power supplies, you might know how hard that is to achieve - but I'll cover that later:

And as I already touched on external PSU issues - I decided I want them separate from actual PCs, so I was initially building a separate module for them. I made this decision also because of the issues @geerlingguy mentioned in his video - you just can't find any decent PDU for 10 inch rack:

This rack requires a 3D printed and some skills in 3D modeling if you want to have a neat look of all your custom stuff - even the one that has no 10 inch rack mounts, but that also let's you get such setup for less than $50 and be able to extend it for any possible changes to your homelab later