Create an application for Mac OS that creates a virtual drive. That virtual drive, shown in Finder, lists files and downloads, when the file is opened. The data (files list) and file data is consumed by web services.
Will have an icon on Mac top bar, where they can access to their login, status, settings, last files used, etc.
The settings screen will contain things like cache, which files / folders to be stored locally.
The app must use cache lists and can't hang up the finder while is communicating with the server.