AFAIK, there is no PreviousPageObject or plans to implement one. IMO, there isn't really a need. The behaviour of the NextPageObject varies depending on which client is being used. On iOS (and Android?) the NextPageObject provides an "infinite" scroll UI. Other clients tend to just display them as a menu item. In either case, the client should allow returning to the previous "page". Either by scrolling back up or using the "back" command (which varies from client to client).
Are there then a "history -1" or a way to make a DirectoryObject not be a part of the navigation history ?
Example.
User clicks on a DO, this DO contains a DO for back paging(except for page 1), the videos and a NextPageObject.
When user hits the back DO, a DO is added with Previous Page, but when the user then hits esc (PHT... not sure what shortcut to use with remote / other clients) the user jump up one level in the tree.