Oznium actually sells some LED Dome Light replacements that are 5×5 LED arrays that include common bases with the LED array.
I thought that these modules would fit inside the BMW Bavaria trunk light housing that uses a 8.5 x 37.4 mm Festoon bulb.
The photograph showing the trunk is a little misleading – it’s actually about 4 times brighter than the bulb with the filament – you’d have to strain to read by the light.