Very impressive One Pager that renders your uploaded design within a mobile device, allowing multiple 3D angles and colors. Make sure you read their About section explaining their vision for in-browser live-rendering.
FYI: if you need an array of device screenshots, One Page Love offers a $10 service called Screenshot Concierge.
Our vision is to one day deliver a browser based stock photo market, where users can live-render photorealistic photos. We’re urgently looking for people to support us in any way. Especially 3d artist that could help contribute 3d models for other devices.