The newer macro lights for Nikons DSLR are the R1/R1C1 with multiple flash mounted on a ring fitted to the lens. These have better flexibility than fixed ring flash.
I have the most basic SL-1 ring light (not flash) for the Coolpix series and do use it on occasion. But the LEDs can leave an ugly reflection unless I am careful.
The best results I found is by using multiple remote flash units. This is done in the Nikon system by wired remote or the newer CLS wireless components. Almost all modern Nikon DSLR can use these remote components. There are older flash which works fine as slave unit and literally can cost $20 to $30 each today.
Here is an example taken with three flash units.
http://i48.photobucket.com/albums/f2...8/DSCN9129.jpg
This subject is about 2.5 inch tall.