Amazon just announced that CloudFront now support custom origin, which means users can use their own server as the original content storage. You don’t have to use S3 as origin.
It is more flexible for users. Easy to integrated with CMS system.
Her are some reference of custom origin.
Defination of Origin Server.
Developer Guide: Appendix Custom Origin
Right now, AWS management can not create CloudFront with custom origin. But, if you have a distribute with custom origin, you can manage it in AWS management.