Digital Video Player for Car

I need help finding this if it exists at all:

Basically a hard drive that I can burn my dvd's (kids dvd's) onto and then play them on car video screens for long drives.

I hate dealing with DVD's and woudl love the ease of having 20 or 30 movies ready at any time for a drive....

Thoughts?

Vudu will let you purshase movies and then you can disconnect the box and use it somewhere other than your home. The catch is that you purchase the movie or tv show, it expires after couple of days. It's a rental service.