Too bad there is no ray traced reflections in the default shader. Could than do a barely visible (transparency) sphere with barely opaque (opacity 0.1 or something (if there was a way to have it not actually disappear)) and have some glass shadows. Without the shadows it looks odd, but when using merge shaders or reflection over a default, it causes the shadow function in the default shader to become what looks to be about 0.75% opacity. Even if you change to minus 0.00000001 or what not. Glass shadows should be investigated, something sorta needed for a glass shader.
Here is an example of the spheres shadow issue, and an example of earlier help file before power went out, but lots of posts since then.
