The Seaberry is one such design, as demonstrated by [Jeff Geerling], giving the CM4 a Mini ITX formfactor and a ton of IO. (Video embedded after the break.) The Seaberry sports a full-sized x16 ...
The best Mini ... ITX cases to test airflow, cable routing, and support for motherboards and radiators, among other things. You'll find my recommendations below. If you're more of a 'go big or go ...