To solve this problem, I decided to put all the DVDs in old CD jewel cases and keep them all in the van. This way, the movies are available in the house and on the road as well. Less arguing and disappointment all around. And that is something we can ALL get behind! And as it turns out, they take up less space in the van this way too. Win!
Our littles aren't readers just yet, so we rely on the picture on the cover to remind them what each movie is about. So, for each movie, I did a google image search for the movie poster. I then printed it on card stock and cut it down to 4.75"x4.75" to fit the jewel case cover. This way we can still show them the picture. I also took apart the back of the jewel case, turned the paper inside out and wrote the title of the movie on the spine. This way it will be easy for me as I am driving (or co-piloting) to get the movie they want. It's not exactly what you'd get in the store, but it's functional, and that's what matters to me.