Such a thing should be easy to make. Cavers have recently made the
transition to LED headlamps that put out a lot of light but use little
power. Their need for power conservation is much greater than the
anchor light application so I'd be surprised if such a light could not
be adapted. The easiest thing to do would be to use a cluster of LEDs
that put out light into a fairly small solid angle and use a toroidal
CPC reflector to redirect the light into an annular cone shaped beam.
If somebody built a high quality LED Anchor light with low power
consumption with an ON at night and OFF in day, how many people would
buy it (assume less than $50)?