PopSlate's 2nd-gen iPhone case offers a 4.7" 800x450 E Ink display for the back of your phone. The case adds 4mm to your phone, and connects to the phone via a Lightning connector that also charges your phone from the PopSlate's battery. The PopSlate 2 supports iPhone 6, 6S, 6 plus and 6S Plus.

PopSlate 2 photo

PopSlate launched a crowdfunding campaign to finalize development and production, and they already surpassed their $75,000 target.

E Ink display info: 
4.7" 800x450 E Ink