A new video has emerged comparing a purported front panel from a next-generation iPhone to that of an iPhone 4S. The video, posted by parts company Etrade Supply and available for viewing in embedded form below, is accompanied by a blog entry that offers up several still comparison photos. Together, they show that the next-gen iPhone’s screen will indeed be roughly 4 inches in size. The next-gen panel is also shown to be thinner—0.91mm…