Folder tree in Finder sidebar (or stuck to Finder)

Is there a Finder plugin (maybe SIMBL plugin) which allows one to see the directory structure in the Finder's sidebar (instead of Favorites, Shared, Devices) or in an attached window? Something like this: There is Cover Flow, but it's not what I need. Also I don't need any Finder replacement; I just want to fix this missing feature in Finder.