Since 2005 or something the ambulances, limousines and hearses built by coachbuilder Nilsson are registered as Nilsson V70 Ambulans, Nilsson S80, Nilsson 300 (special 300mm longer Volvo S80) etc.

The different models are crash tested and EU-approved as Nilsson.
This is because it is so much rebuilt it can no longer be called a Volvo.

So, the question is, should these still be listed as Volvo V70 Ambulans Nilsson?

Examples:
http://www.imcdb.org/vehicle_774608-Volvo-V70-2007.html
This is listed here as a Volvo, but as Nilsson V70 in the swedish vehicle register (and also EU-approved as a Nilsson)

http://www.imcdb.org/vehicle_147642-Wiman-9000-1996.html
This is registered in sweden and in the IMCDb as Wiman 9000. Wiman is the coachbuilder, and the special chassi is made by Solstad.

Indeed, if we follow the logic used for many other vehicles, we should list these under the Nilsson make.

Yes. The difficult part is to know when they started to be registered as Nilsson (one way is too look in the Swedish vehicle registry (a big job, except for some post where it is already mentioned, but I can help if it is necessary)

It is not a big problem if we are off for a few years.
Here is the list with all the vehicles having Nilsson somewhere in their name:
http://www.imcdb.org/search.php?resultsStyle=asList&sortBy=2&yearFrom=&yearTo=&makeMatch=- 2&make=&modelMatch=0&model=nilsson&modelInclModel=on&modelInclExtra=on&origin=&madein=- &madefor=&role=
To make things easier, I would say that we use Nilsson as make for the Volvo S-something and V-something, and keep the old 3-digit models as Volvo.
What do you think?

There is also one Mercedes in there:
http://www.imcdb.org/vehicle.php?id=88546
the only one with an actual model name
Maybe it should be listed as "Nilsson Laholm" rather than Mercedes E-Klasse?

If they call it "Laholm" then it should be listed like that (just like the Nilsson S80 300 (with Volvo B8444S), but there are none of them listed here (and probably never will, they are not very common among the public, mostly used by the government, embassies etc. In movies they use normal Volvo S80)

But, I have actually sent a mail to Nilsson Special Vehicles, and when/if they answer I will post more information. But until then, Nilsson V70 (or S80) Ambulans, Nilsson S80 Limousine and Nilsson S80 Begravningsbil will be perfect.
And Nilsson Laholm for the Mercedes.

OK I'll do that tomorrow if I don't forget

Here are they: http://www.imcdb.org/vehicles.php?make=Nilsson&model=

Nice!
Good job