This was designed in OpenScad.

One of my graduate student friends needed a specific mounting bracket for a LED to be flushed on the face of a surface to get better lighting.  So the idea was to have a hollow cylinder for the cords to get to the LED, and have the LED sit on the top of the cylinder.  The idea was abbandoned later on, but I still had this design so I put it here.  I updated it a bit to remove excess plastic if cost of plastic is a concern.  With the base settings, it costs about 30 cents to print.  Compared to the base setting with the option to remove plastic it costs about 20 cents.  It is very similar to this design, which is $14.39.  The differences is there is no switch to turn it on or off, and there are no threads for this design, since it is just to hold it there with friction.