ViewSticks (http://www.viewsticks.com) is a new, US$19.95 headrest mounting system designed to be compatible with all iPad cases and installed and removed without tools. The system will install on any automotive headrest that has post style attachments.
It will also hold and support the iPod touch, iPhone, all tablet computers and Smartphones as well as most DVD players. ViewSticks can be switched from seat to seat or car to car.