In CDRS, we could move the default light dynamically relative to the model

By moving it left and right, up and down etc .. you would pick up poor highlights and reflections in a body panel

I've just been playing with some CAM software, which (for reasons other than the above - and unclear to me) has such a feature

Basically, it's a little box that allows me to dynamically change the "Primary Light Source Vector" via some sliders.

How about it Tim. This might not be too hard to implement - and would have the added benefit of allowing users to choose their default light setup !!