A part claimed to be the back plate and sides of the next-generation iPhone has appeared online. 9to5Mac has posted a photo from iPhone repair shop iFixyouri, showing a part that closely matches prior artist renderings posted by iLounge in our next-gen iPhone specs report. Most notably, the back plate does in fact show an aluminum plate taking up the majority of the rear of the phone, with what are presumed to be glass panels at the top and bottom;…