M4V Converter Plus can remove the expire limitations.
Answer by Techas Jeus:
For the movie rentals, you have 30 days to start watching a movie after you rent it. After you start watching the movie, you have 24 hours (in the US) or 48 hours (elsewhere) to finish it. You can watch the movie as often as you like until it expires.
If you don’t start watching a movie within 30 days, you must rent it again.
Movies you rent disappear from your iTunes library when the rental period ends.
That is, you rent the movie, and you don’t start watching the movies, there is no 24h limit.