Loved the original design but only had a stack of Rpi3's in my cluster. I threw it into Tinkercad, swapped the inputs around and added a different vent to the top of the unit.

Also, I changed up the fan side panel to make it one big input (the original version was setup for the Pi4).

Can confirm it fits the Raspberry Pi 3 Model B boards perfect!

Just waiting on the OLED screen + screws to show up so I can finish putting this all together.