I have read several of the above in fairly reputable publications over the years, and
several hours of searching the web recently turned up maybe a hundred sites repeating these "facts"
along with a handfull of sites with accurate but rather vague info, so I finally
decided to remedy the situation myself.
So, I grabbed a coral snake that had died of natural (but unknown) causes at the refuge and has been sitting in the freezer forever. On one side it had a replacement fang growing in (maybe half the size of the primary fang), which fell out during cleaning. The photos below are of that fang under the microscope at 40X, followed by a picture of the skull.
This snake was about 22 inches (560 mm) long, the skull is 5/8 inch (16 mm) and the fangs are perhaps 5/64 inch (2 mm).
As you can see, this is a fully formed and enclosed tubular fang like any other elapid fang.
The skull looks basically like the skull of any cobra, with the fangs in about the same place, and the primary fangs look fairly close to the same size relative to the skull. They would have no trouble penetrating the skin on most parts of the human body, though it would be unlikely to make it to a major blood vessel.