The 3d printing crowd love organisation systems. I have used one to tidy some drawers full of cables and things. I also have a little shelf unit I printed for my audio interface. You are limited on size of parts and somewhat on strength, but there is a lot you can do. Specialist racking can be expensive, but people will hack things like Ikea shelves as an alternative. I'd be interested to see what you used. I love to see things like studio set-ups to get ideas.

!BEER