General "wiring points" for DVD, TV and other accessories

[wm_hatfield]

I would like to create a primary power source panel in my trunk area for add-on accessories such as DVD, TV tuner, LCD displays and similar items. Four circuits are desired: always on, on when engine or ignition is, on when key is in accessory position, on when headlights are one, and on when the car is in reverse.

The sources should be not interfere or cause errors to be generated in the OBC (such as causing a greater current drain in the back-up lamps and issuing an error or such as changing stop lights to LEDS which draw less current than standard and issuing an error as a burned out bulb).

Any ideas as the best and most accessible sources in the trunk area (to avoid having to run cabling all the way to the fuse box)?