This is a general question of how to best manage large downloadable content on mobile devices.

Lets consider a situation whereby a mobile app needs to download a number of very large content items, like HD videos, that are over 500MB but under 2GB. Now, lets assume this content delivery system should be scalable. Would it be a fair assumption that:

• A reputable cloud service would be needed - if so, what is a reliable and cost effective cloud service for mobile devices based on anyone's experience?
• Large content downloads should only be attempted over a wifi connection, so the end user doesn't incur large costs, e.g. when travelling.
• Downloads should carry on in the background if possible, as the user won't want to wait in an app for long periods. If the downloads don't finish, or the OS quits the app, all downloads should carry on when the app is next activated?

Are there any other pitfalls anyone may have experienced when managing large content on mobile devices?

Thanks.