Apple just recently let Apple TV users re-download and stream TV shows they've previously bought. According to AppAdvice, this same sort of feature could happen for movies too. It's supposedly part of a bigger feature called iTunes Replay.
In the very near future, AppAdvice says that "TV Shows as well as Movies in iTunes will be given little arrow indicating whether they're "iTunes Replay eligible", that is, available to be downloaded subsequent times." You can access all the movies you've bought as far as January 1st 2009 and possibly even stream them to your Apple TV and iOS.
The whole initiative makes sense and all (especially with iCloud on the way) but is really something Apple should have done YEARS ago. Come on, re-downloading stuff you've already bought? Isn't that the first amendment in Internet rights or something? AppAdvice is saying this feature will go live in the coming weeks. [AppAdvice via BGR]