This is an awesome idea. I would love the option to upload a short video clip instead of a gif though, and have it take 10 evenly spaced frames from the video. My nieces (ages 8 & 10) would love to use this to make prints of themselves in action, but it would be easier for them to be able go straight from a video taken with a phone to a printed product.
Thanks! We currently do support Vine and Instagram video, and you can pick a short clip from there. Processing all videos in all formats is a little tricky right now and it's helpful to have the pre-constraint of those social networks. Taking video from a phone is a great idea though!
Pretty sure you can do that in Photoshop and/or specialty apps. See "Cinemagraphs/Cinemagrams".
For example: http://www.reddit.com/r/Cinemagraphs/