We’re using this screen: http://www.qualitymobilevideo.com/lcd4l.aspx
It’s a bit low contrast and the pixels are chunky. But it’s small, thin and light. And cheap! The image on the screen is being fed via composite signal from that black blob to the lower right of the photo. The one with the red paint smear on it. It’s not a pinhole camera, but it has such a small lens that it behaves a lot like one. Both of them run together on a pack of eight AA batteries.