I have recently bought a bunch of British Leyland promotional films, and I wanted to put them here, but I'm not sure about your opinion of commercial films on the site, since SAAB Suite is listed , but I'm not very sure, so I prefer to talk it here before.
What do you think about it?

Depends what kind of promotional films these are, I guess... are these ads or more elaborate films?

They aren't just ads, they are films showing the developing process of the car

Were these films sold officially in shops or something like that?

Yes, this is the DVD I've bought: http://www.motorfilms.com/videos.php?id=110

If they sell the DVD, I'd say that we can list it.
One movie entry for the DVD, with eventually episode number for the various films that it contains.