I have been searching for a standard light bulb extender that is less than 1 in. in length. Is there such a device? Ideally I would like one that would extend the socket 1/2 to 3/4 of an inch. Can anyone help me locate one?

Not sure what you are talking about, or why you would want such a thing.

If your light socket is recessed too far, the usual way to fix that is with something called a mud ring or plaster ring. This is an extender that attaches to the box in the wall, and makes it larger. Then you re-attach the light fixture to this extended box.

These are available in a range of sizes, starting with 1/2".