It appears that the rack posts are just chopped/hacked from some other rack ... but where are people sourcing these little 10" wide rack shelves ?
Also, the bottom component - is that a patch panel or a switch ?
Plenty of 10” kit about e.g. https://datacabinetsdirect.co.uk/soho-10-inch-data-network-r...
10” soho rack appears to be magic search phrase
I've see a rack similar to the in the article before and can't find it now, but one way to recreate would be to buy soemthing like this a use a 10” blanking plate instead of the 19” one https://www.amazon.com/Procraft-Desktop-System-Washers-DTR-1...
Lots of music gear shops sell desktop racks BTW