A-HA! It's supposed to be an empty scene when I tell it to be an empty scene, right?? Yet apparently there IS a ground that I STILL have to hide even though the scene was told to be empty without anything in it. ARGH!

Ctrl+G then render with nothing but black background prop, no light and 10% ball prop with hborre's mat on it produces nice soft pointlight effect.

Same with shrvdavid's shader on it:

I wish the ground behavior was consistent ie. if I tell the chooser I want an empty scene it would give me just that ie. a completely empty scene.