The thin film covers iPods, laptops, and other devices completely; or they even sell custom screen-only versions. The prices are moderate (around $26 for a full iPod Touch cover) and come with the film, cleaning solution, and a small squeegee to get out any air bubbles.
By far one of the best scratch resistant methods I’ve used to protect my valuable screens that take a beating every time I hit the road. Of course a shiny clean screen is pretty useless if your device doesn’t have any power. Try using a solar backpack for the outdoors or bring an outlet USB charger.