I could improve it with more symbols.

Playing around with the concept of symbols, I found out I actually needed to see the symbol location in both 2&3D views. At the same time I only wanted the lightsource itself when rendering. Very similar to the included light sources, but I wanted to make the mounting points more visible.

However, it is also reasonably easy is to do the same for wall-lamps - and without the light source: electric sockets, switches etc. For cable pipes I suppose one could use the arrow set or use dimensions. Attributes for reference in the SF thread: 2DSymbols

ok