Hello,
I revive this thread (from September 2009), because I am interested in a folder tree view, too.
It was also asked in June 2005 (see: Folder tree view?).
And also partially in March 2017 (Edit TAG only F2 key; Internal music player; tree view for folders).
The first linked thread mentioned a "roadmap"... well, I used the search function and found something from April 2003 (Aktuelle Hinweise!) written by Florian himself.
Unfortunately he wrote that tree view and commandline was/is not planned 
.
But so many years have passed. Maybe some ideas have changed through 17 years 
.
Dear admin(s) is there anything planned for tree view and/or commandline 
?
Would be nice. Thanks for your kind attention 
.