Dual Voltage Ceiling Light: "Pluto 8816-E14"
AC: 110 volt, 25 watt incandescent bulb / DC: 12 volt, 20 watt Xenon bulb
Recessed, low profile - from SailorSams.com

AC-DC Dual Voltage Light* allows you to to alternate between shore power and battery (or alternator) power. -

Pluto 8816-E14
Photo above shown not installed.

Dimensions:

Screw mounted.

* SAFETY NOTE: These dual voltage lights must be powered by only one voltage source at any given time. In other words, you must prevent both bulbs from being on simultaneously, as overheating may occur! To help prevent accidental overheating, a  relay can be incorporated into your circuit. For example, wire the 12 volt bulb to be fed through the normally closed contacts of a relay, and wire the 110 volt bulb to be fed through the normally open contacts of the relay. Control the relay coil with the 110 volt source. This way, 12 volts normally will reach your 12 volt bulb through the normally closed contacts, but whenever 110 volts is applied, the relay coil will open the 12 volt contacts, interrupting the 12 volt supply. Simultaneously, it will close the 110 volt contacts, energizing the 110 volt bulb. If unsure of how to accomplish this, consult with a licensed electrician.