There's something about supposedly-leaked iPhone HD components that make us instantly suspicious, so forgive us if we seem unnaturally sceptical of this purported fourth-generation iPhone display. Spotted on a video from SmartPhoneMedia, who claim to have received the component from a "very reliable source", the display is slightly longer than the current iPhone 3GS panel but also narrower.
Video after the cut
Of course, they're also covering themselves by pointing out that "Of course we can't 100% guarantee that this will be the design for the iPhone 4G our sources are very confindent [sic] that not much, if anything will change." Still, we can't see people saying this is a Photoshop mockup.
Even if it's a real panel/digitizer, of course, that doesn't mean it's actually for the next-gen iPhone. It could be, as CrunchGear suggest, a prototype or a test display, or it might even be a panel used by one of the thousands of iPhone-copies.