I like the idea of stacking tech, too. I don't have a 3-D printer to make cool stuff, but I did purchase some metal stands with adjustable height legs to store computers and hard drives more efficiently. I even got one that had drawers and pencil/pen holders. All metal with holes/screen design to allow maximum airflow.
I started with a set of two and liked them so much I bough two more and then began buying them for my family. They function as monitor stands, Mac Mini stands, laptop stands, podcast gear stands, etc. The adjustable legs are a nice bonus. Now my studio sets have tech specific areas and stay cool because of the screened design.
Geez, I had no idea I had so much to say about a simple purchase. Thanks for posting about your cool and functional 3-D printing. You've got me thinking about some other items I've had on my wish list for my studio space. Organization stuff which some may think is boring, but I can totally geek out once I dive into it.
RE: Expanding the 3d printed rack