We have a post light in the front yard that looks something like this:

http://www.elightspot.com/Livex-7558-04.aspx

At Christmas each year, I replace the regular light with a Santa light,
which fits nicely inside the housing.

This year, I wanted to replace the whole light fixture with a large
jack-o-lantern cut from one of those artificial pumpkins. But in order
to make that work, I need to remove the whole assembly, take it apart,
and rewire the light socket to the cap. This is a tedious process that
will surely involve losing small screws and nuts and multiple trips to
the hardware store.

It occurred to me that the whole process would be so much simpler if I
could find another cap and light socket. Then I could make a whole
separate assembly.

I have been unable to find a source for the cap that will fit over the
3" pole. I called several online yard lamp stores. They only sell the
whole assembly.

Any ideas where I can get a cap for a 3" pole with a threaded hole for a
light socket?