There is an article in this months BMW Car Magazine giving details of a new "Advanced DVD" system for the X5. The picture shows two 7" screens mounted on brackets so that they sit high up behind the front headrests. They are not integrated into the headrest the brackets look like they fix on to the back of the rear seats. Comes complete with a boot mounted 6CD/DVD changer. Doesn't mention price. Doesn't mention price. Unfortuantely I don't have a scanner so I can't post a copy of the article.

Seems to be a dealer fit alternative to the system you can spec at build time.