Well, assuming you've got the gainroot add-on, there's always the shell. I'm happiest in the shell, so do almost all of my file management from there.

If that's not quite your bag, then how about just starting this as root:
http://maemo.org/packages/view/mc/
"""
midnight commander - a powerful file manager

GNU Midnight Commander is a text-mode full-screen file manager. It uses a two panel interface and a subshell for command execution. It includes an internal editor with syntax highlighting and an internal viewer with support for binary files. Also included is Virtual Filesystem (VFS), that allows files on remote systems (e.g. FTP, SSH, SMB servers) and files inside archives to be manipulated like real files.
"""