Ben,
I've got these portable dvd players that mount on the rear head rests in a vehicle.
I'm planning on removing the DVD guts, then replace with a R PIv3 with kodi installed.
Since this is to be designed with my kids in mind, I also plan to add in the necessary module for wireless game controllers.
I was wondering if you would be interested in doing a build, I could send you one of the sets that I have.