Joe, although the rules are specific about navigation lights and anchor lights, there is absolutely nothing to prevent you from putting other "deck lights" or marker lights on. This is common practice in larger boats. In crowed anchorages, where there might be an influx of boats early in the night, I would leave the spreader lights on, which show the entire outline of the surface of the boat--plus we also put a small light on the bowsprit and on the aft davits--One of our boats was 62 feet long, and a 360 degree anchor light up 63 feet off the water is difficult for many smaller or even medium sized boats to see.
If you watch the commercial vessels or large mega yachts they will almost always have lights on at the deck level.
We use the Davis Mega/utility light often in the cockpit to destinguish the smaller boats at night. With the small bulb this only uses a few milliwatts. We have other friends who use the solar lights. Don't know about the current generation, but when we first used them, they often would not last the entire night.
Occasionally at Catalina, we will put a small flashing red LED on aft part of the boat, to make it easy to find at night. Again this is not a light which can be confused with a navigational light--which is the basic principle when using other lights. One of my pet peeves is the dinner ships, which string christmas or colored vinyl tube lights all over the boat, so it is hard to distinguish the navigation lights...When we are running at night, the only lights beyond the standard navigation lights are some red night lights in the cabin, if we need them. These are small LED's which are not directly in the skipper's eyes.