Does iTunes in the Cloud apply to Movie Rentals?
iTunes movie rentals originally purchased on a computer can be moved between devices as many times as you like during the rental period but can only "exist" on one device at a time. To move it between devices, use iTunes with the device you want to put it on. See this Apple support article. Steps are:


Connect the device and select it in iTunes.
Click the Movies button.
Select the movie, and then click Move.
After all movies have been moved, click Apply in the lower-right corner of iTunes.


To answer your direct question: no, rentals do not currently exist in the cloud.