I am thinking of buying a dvd player for use by small children in the car. It is an mpv though so one child will be in the back row. What should I look out for in terms of screen size and flexibility? I don't want an expensive one either though it should be durable. It will not be for long journeys and is intended more as a distraction for one child who just does not like being in the car for very long. Any suggestions would be welcome. Thanks