An official "making of" video from HTC that details the company's efforts to create the newly announced HTC Evo 4G LTE has a little surprise inside: for a brief moment, it shows off a prototype that appears to have the same dual-camera / dual-LED flash layout that's featured on the Evo 3D. Obviously the company hasn't announced anything, and this could just be a lonely smartphone prototype shell that will forever sit alone in HTC's labs, but we wouldn't be terribly surprised if a 3D version of the updated Evo is on the way — seeing as the Evo 3D similarly followed much of the original Evo 4G's design. So is this a surreptitious attempt to hint at a 3D follow-up, a careless video edit, or just a meaningless prototype that will never see the light of day?