I found the now deleted Raspberry Pi 4 / Pimoroni NVME base case with LOTS of ventilation that was a remix of https://www.printables.com/model/722026-raspberry-pi-5-case-for-pimoroni-nvme-ssd-base-opt a while back. Printed them out and wanted to bundle them together for a pi cluster where each node is still independent of the others. Print 4 end pieces per cluster, and 2 mid spacer pieces per space between nodes. So for example if you have a 4 node cluster, you will need 4 ends and 6 mid pieces. Cinch it all together with a long slim zip tie . This should allow plenty of airflow between the cases, and keep your pi from slding around. This was easier for me than to redesign the rack mount cases…