Looking for a file manager

I'm searching for a PHP-based file manager script and was wondering if anyone had any experience.

I need to give users access to certain directories, for example:

v1/username/
v2/username/
v3/username/

Where the username and password are stored in a database table already. (They're usernames from our installation of vBulletin forums).

So I guess what I'm looking for is just the file management framework, so that I can write my own authentication.

A lot of the file managers I've found are very focused on single users (i.e. this is for one person to manage their own site).

Has anyone got any recommendations?

Thanks,

Antun