According to AppAdvice, Apple may be prepping a new re-downloading and streaming service called iTunes Replay. The service would let you re-download select movies and TV shows from iTunes and stream that content to a variety of iOS devices.
The Replay service will supposedly let you access shows that you purchased as for back as 2009 and will stream them to your Apple TV and iOS devices. Similar to Amazon Unbox, the number of downloads may vary from clip to clip and may be limited in number.
This isn't the first time we've encountered this rumor; bits and pieces of it have been floating around since 2009. The only difference now is that with iCloud, Apple may have the underlying infrastructure in place to host such a streaming service.