It looks like I will be able to get some custom readouts for spheres, cylinders, and cones.

Like when you select a sphere (either a whole sphere on its own or a sphere face sub-object out of a larger solid) instead of showing the Size: label, it will show Radius:

The way the readout works, is that for a general object or multi-object selection, it shows Size: which is the bounding box size.

If you have a single object selected, it can show information about these types:

Line - the length of the line.
Circle or Arc - the radius
Sphere - radius
Cylinder or cone - radius + height

- Michael