Permit aircraft should be approved to fly at night providing the owners can produce evidence to the controlling authority that the electrical system has sufficient capacity and redundancy. There is a world of difference flying at night when the sky is full of stars as to when you run into unseen clouds particularly those where icing conditions may be prevelant.
For night VFR you need an electrical load analysis, (load shedding and how many minutes available after alternator / generator failure) and assessment of the cockpit lighting in realistic conditions (feedback from canopy, nav lights and beacons in VMC and in cloud).
A dark cockpit on a black night is a totally different environment to that on a sunny day and all aspects need to be taken into consideration. You cannot assess this in daylight or simulated night condtions as the shadow fall is different.
You cannot rely upon a headband mounted torch to solve inherent design / lighting problems. You still have to aviate, navigate and communicate and just as MP3 players and mobile phones can be overbright in the early hours of the morning some of the GPS units need to be overbright to read the details.
Believe me if not correctly lit the instruments do not provide a reassuring glow when the lights go out, they are not luminescent!