Old computer power supplies are a great resource for ham radio gear, CB radios, chargers, or any other item that needs a regulated 12 volt source. Many of these older power supplies do not have an on/off switch on the unit. By tapping the green wire and any of the black wires on that connection plug that goes to the motherboard a standard switch can be wired in.
Another benefit is that these supplies have several wired 12 volt and 5 volt outputs. A custom supply with USB plugs and several cigarette-style receptacles could be constructed.