We’re going to cover all the steps required to turn a cheap shell of an arcade machine into a Linux-powered multi-platform retro games system. But that doesn’t mean you’ve got to build the whole system at the same scale.
You could, for example, forgo the large, heavy and potentially carcinogenic hulk of the cabinet itself and stuff the controlling innards into an old games console or an even smaller case. Or you could just as easily forgo the diminutive Raspberry Pi and replace the brains of your system with a much more capable Linux machine. This might make an ideal platform for SteamOS, for example, and for playing some of its excellent modern arcade games.