Summary

This is "the Cube", a practical case for a raspberry pi 5 (4 and 3 will fit as well I think, but not tested) that allows several options.
It is a remix, if you like you can use the fins from the original design, to make it look like a NeXT computer, but I choose not to.

I made different fronts, a closed one, one that allows an I/O pin ribbon cable for controlling e.g. robots, and one that allows a flat cable for a camera module and/or PCIe. You can modify the front yourself to suit your needs. The fronts are easier to print compared to the original design, they can lay flat. I added some 3mm holes for the LEDs, which makes mounting (and glueing them in place) easier. Connect the LEDs (with resistor ofcourse) to PIN 2 or 4 (5V), PIN 6 (GND) and PIN 36 (ACTIVITY). You have to program PIN 36 (IO 16) yourself (you can choose any pin you like ofcourse, Pin 36 was suggested in the NEXT case design)
Note that the fronts are a very tight fit and maybe do not need the mounting option I added, except for maybe the one for the ribbon I/O cable.

I added a slot so you can install an extra PCB for I/O funtions. In the back there is the option to install two melt nuts for a frame to keep the PCB in place when it is smaller than "the Cube"'s slot. Or you could add a fan-mounting frame to add an additional fan (4cm)

You can mount the back using melt-nuts, but I added a 2mm hole below each so it is also possible not to use melt nuts as in the original design, but use 3mm screws instead. There are two backs, one which matches the height of the front and another lower, which saves a lot of time printing. Also the back now allows the throughput of the camera and/or PCIe cable.

The sides have two holes. This allows you to mount "the Cube" onto an extension case or vice versa, for instance for a USB SSD disk. The holes allow the insertion of a 3mm screw to fix the extension in place. Also an extension can be mounted on top, e.g. for a camera module, and fix it with a screw

You need a few items for the internal cabeling, you can find them on Amazon or Ali, etc

--90 degree (up/down, otherwise it may block the HDMI connector) USB male connector with bare wires. I used a two wire version but note: for full functionallity, you also require the CC line and D+/- lines for communication with the power-supply (Pi4 and 5). In that case you need a 4 wire cable. You can also cut an existing (5A) power charging cable open.
--USB-C panel mount female (6 wire variant (=with CC wires) preferred)
--Inline 2x female HDMI panel mount
--micro-HDMI male, 90 degree up, to HDMI male

For the on/off switch I provided a 6mm hole. Note that if you use the original pi power supply, you also need to switch the CC and D+/- lines. If not this may lead to issues with the power supply. So you will need a 4 lines switch.

Refer to images as suppliers change all the time. For USB I used a flat 90degree angle version, an 90degrees up would be preferable but I couldn't find one quickly.