A gem we ham operators use for 12v distribution is Anderson Power Poles.
They're polarized so you cant hook them up wrong, and never come
unplugged (unless you want them to). 

Powerwerx makes a beautiful 12V + USB panel. 

http://www.powerwerx.com/powerpole-power-distribution/rigrunner-4004-usb
.html

They also sell the Anderson connectors that you can put on your 12v
equipment to make it compatible. May seem a little pricey but you have
to realize this is industrial equipment adapted for civilian use.

You'll never use a cigarette lighter socket again... 'cept for a lighter

Shawn
87 Syncro "Eeyore"
86 Westy Weekender