Premiere in Germany have a dedicated in-car channel on their F1 coverage (see their website for details
www.premiere.de) from what I know after talking to a friend over there, they can only view one in-car camera at a time and it's the director who decides what you see like BernieVision was here, generally when we get an in-car 5 second clip on ITV, the germans have had 5 minutes worth or so on their dedicated channel then it switches to another
car.
They do get most of the qualifying runs from each car though.
Each car carries at least 2 cameras.
The reason there's no cams on the rear wings is one flew off a car a few years back at Monza and hit Berger's Ferrari breaking the front wishbone, if it had been a few inches higher it would have killed him so they stopped putting the cams on the rear wings before something happened.