"However, if one is going to slow the boat and go below and sleep a few hours, I'd rather see the two lights signifying NUC than to keep waiting for the boat to take some avoidance action that's not going to come."
A simple system would be to show a 360 white light.
It would read as an anchor light or a vessel being overtaken.
With many of the commercials running 15-25K , the white all around would read as a vessel to be avoided.
Perhaps not legal , but lots better than running lights that loose 80-90% of their viz by being behind colored glass.
On sail boats there is little chance of being run down as the noise of the engine of the commercial can be heard for miles when below.
On power boats , a radar alarm might work , or a visual scan from a high point should give an hours warning of an approaching vessel.