What if you work for a foreign company that gave you a company vehicle?

I did the same for about 3 years in UK, and it was fine,even the local police and DVLA confirmed that I'm not braking any laws doing it, even though the law is structured in the same way - if you are a permanent resident you can't drive a foreign vehicle in the UK. Except if you work for a foreign company that gave you a company vehicle to use then yes,you can, and there doesn't seem to be any restriction on it.

As far as I know, what you just described is the only "loophole" in existence, and it is supposed to work in any EU country because of some weird nondiscrimination rule. There was even some ECJ ruling on it, if I remember right.

For example: I know of a Dutch guy who leases a Ferrari through a Belgian company he set up for this, because it would cost him twice as much in the Netherlands. There are also examples of Belgian people driving cars with Luxembourg plates, etc. This is not illegal (though it's obviously a form of tax avoidance)

The Danish tax authority has this mentioned in their FAQ [1]. They claim that this is true but, 1) "it is a requirement that your vehicle is primarily used for business purposes abroad", and 2) you must "apply to be exempt from registration tax".

[1] See the question "Foreign company cars" here: https://www.skat.dk/SKAT.aspx?oId=2068721

Might just be their interpretation of the law though. It could very well be impossible in Denmark, but if some EU law is making it possible, local law can't block it (even though they might want it to). And even if local law is blocking it, it might be in violation of EU law.

Given we're talking a €100-120K tax difference on expensive cars, you can always consult a Danish tax lawyer and if he thinks it's doable do it anyway. If the tax authority has a problem with it then, then you just take it to court. Seems worth investigating.