DVDs w/ Cross Platform Commentaries

I have been frustrated how DVDs do not exploit their technology. It is a long list as to what they could do to make better use of it, and hopefully one day I will build that out. In the meantime if you have any suggestions please forward them on to us here. And to tide you over until the day comes with the mega-uber list:

This suggestion from Dan McGuire:
Movie dvds should include a Aiff or Mp3 audio file of the director's commentary, so I can listen to the comments on my ipod or car cd player the day after viewing the film.

How great would that be!