Yes, very nice result, pretty much the kind of effect I have been looking for. Thanks, some good ideas here.

Making the bulbs round and placing a circle of tiny lights around them, really made the difference.

Absolutely. I did not try that. In part because typing up all those light-source properties in the model will take some time. As my objective is a bit different, I need to experiment further: Aim is to make a relatively simple model with built-in lights for a library file. While this is a step in the right direction, there are a couple of things I still need to look at (once the weather discourages after-work trips out in the fjord).

• The rendering of this lamp is pretty demanding on the cpu - slow on a slow computer. Ideally, I would prefer to avoid that kind of bottle-neck. How much is down to the large lamp model, and how much is down to the number of lights I have yet to figure out.
• The approach actually works quite well even if I halve the number of tiny lights surrounding the bulb. Not quite as nice, but still reasonably nice. And it does solve the bulb issue.
• In order for the lamp to light up the surrounding area "through" the lamp-shade, it will, I think, need (large, soft) light-sources outside the perimeter of the lamp itself. While this is possible by using an invisible part of the model where the light-sources are placed, I hesitate, because that would mean that the model dimensions are no longer accurate (at least I have not succeeded in using negative or outside values for the lamp-sources in [font=courier new]PluginFurnitureCatalog.properties[/font]).
• Also, the light-source should have a tint in the same colour as the lamp-shade. My preferred solution would be for the light-sources inside the lamp-shade to take colour from the material in the shade, so that if I change to a green lamp-shade, the model will give off a greenish light, etc. (Having access to the light-source properties from within the model, would help, but I am under the impression that Puybaret does not want to over-complicate the general SH3D interface by giving access to all those lovely properties in [font=courier new]PluginFurnitureCatalog.properties[/font]).
• Just did a quick test surrounding the lamp(-shade) with a light-source. Whether it will work in the .properties file, i.e. the diameter of the lamp extending outside the model, I do not know, but that might just be an idea.

So, anyway, food for thought.

..grandmother used to have lids on top of her lamps, to avoid lighting up the ceiling...

Sounds very familiar. Actually, I still have a fondness for ceilings hidden in the dark. But then, I quite like dark - or at least subdued light - in general.

..answer to the initial question of this very interesting thread...

A thread with lots of twists and digressions, but it would be nice to know more about the initial question too.
ok