Too good write-ups on how to build an arcade cabinet with an RPi as a controller. One is more countertop oriented and involves lots of cutting of wood. The second is a mini desktop one that you 3D print out the panels you need. If you don’t have a 3D printer, you can order the case for a whopping $100.
http://www.instructables.com/id/2-Player-Bartop-Arcade-Machine-Powered-by-Pi/http://www.instructables.com/id/Micro-Raspberry-Pi-arcade-cabinet/