An angle that I don't think anyone has looked at yet is if say Giant does a MTB vid, who distributes it?
Bicycle Brands have distributors for their bicycles. The DVD distributors are completely seperate. In a market like Australia selling DVD's through the Bike distributor is a sure way to move less DVD's. Shop are used to ordering 20 different DVD titles through their DVD wholesaler.
That's problem 1
The 2nd problem is that your local shop sells Kona's, Treks and Canondales (as an example). Are they going to want to stock a Giant branded DVD? Probably not. They won't even have access to it if it is going through the GIANT distributor.
3rd problem. How not to make the video look like on long Ad. Rhyno pointed to the Kranked series. To be honest Kranked pretty much launched Freeriding on the world. It showcased what Canadian riders were doing. The earlier vids with footage from Rossland, Kamloops etc. were at the heart of MTBing in Canada. Is it any surprise that these local boys got sponsored by local companies? The Canadian and NW American companies like Kona and Rocky Mountain were having freeriding evolving around them and these 2 companies were at the heart of it making bikes for their local riders. Santa Cruz as well had their finger on the pulse with the Heckler (Simple, good mud clearance- both essential for backcountry riding in Canada). IMHO that's why those bikes featured in the early Kranks. In the later Kranks the MTB industry had caught up and riders were filmed on what they were paid to ride, Ellesworth, Canondales etc. just like DH racing.
The vids are like they are for a really good reason. The film maker can get sponsorship for ad placements while allowing total freedom to include what they want in the video. That's good for the viewer, it gives us a better product.
Say the boys from Blackphoenix where out shooting the latest Drift vid. Retitled "Raceline" because Apollo had commisioned them to do the whole vid. They have Rennie, Kovarik, Hill etc. bombing down a run, but they have to edit it out because part of the conditions of the "Raceline" vid is only riders riding "Raceline" bikes are to be shown. Our industry is too small for the boys to have a bunch of Raceline bikes to lend to good riders who aren't riding a raceline bike and the really good riders that you'd want to see in the video are signed to other brands anyway.
Not a recipe for a great vid in my opinion.