As stated in Apple WWDC 2011, the new iTune with iCloud allow users to re-download apps that previously purchased on the iTune App Store. According to CDFXapps, the iDOS app, which has been banned by Apple, can be re-downloaded from the purchased section.
The new iCloud features “Purchased” tab next to the “Updates” tab in the App Store. It allows users to download the apps to any of the iOS devices that doesn’t already have. You can also download the apps that have been removed from the App Store, if you have previously purchased it. This feature does appear to be limited to applications removed from sale by the developers and not applications removed by Apple for infringement, violations of App Store policies and other resons. In the meanwhile, some of the previously banned apps are still available, such as the iDOS app and Tris. It is unclear whether this will continue being the case for all apps with the iCloud. They may soon not be available for download.