The same 12 volt cigarette sockets and plugs from Marinco can also be purchased from Digi-Key
Socket: AS212-ND ($2.66 ea.) Picture
Plug: APP-003-ND ($2.07 ea.) Picture
I'm putting these in various places in my bus for 12v power. Typically for things like lights, fans and small (75watt) inverters. I'm sticking with standard cigarette style for compatibility reasons.
I am using a regular 120v light switch to switch 12v power to lights. The switch will actually be turning on an inverter which will be wired to a 4' fluorescent light. Sort of an 'on demand' inverter which will only be on when in use.