Where is my rented movie in iPad?

If you rented and downloaded it on your iPad then it should be in its Videos app (it won't show in the Purchased tab for re-downloading, nor in the rentals tab on your computer's iTunes) - if it's not in there then do you have a film age rating set in Settings > General > Restrictions that is hiding it ?

If you search for it by name via the iPad's spotlight search screen (swipe your first homescreen to the right) does that find it ?

You could try a soft-reset and see if it shows after the iPad has restarted : press and hold both the sleep and home buttons for about 10 to 15 seconds (ignore the red slider), after which the Apple logo should appear - you won't lose any content, it's the iPad equivalent of a reboot.

Otherwise, and if it's not still downloading in the Downloads tab in the iTunes store app (the tab will only show if there are downloads outstanding) then try the 'report a problem' page to contact iTunes Support and se if you can get a re-download: http://reportaproblem.apple.com

If the 'report a problem' link doesn't work then you can try contacting iTunes support via this page : http://www.apple.com/support/itunes/contact/- click on Contact iTunes Store Support on the right-hand side of the page, then Purchases, Billing & Redemption

Do you mean that you powered it off or just put it into sleep mode ? Unless the film is hidden by an age restriction then you should be able to find it in the Videos app, and by its name on the spotlight search screen. I assume that you have enough free space on your iPad for it (Settings > General > About > Available) ?

But you will probably need to contact Support for a redownload