How about a File system browser with NTFS and SMB support? Something that could be used to move, copy, and delete files from an external USB drive. Would be nice if I could transfer files from my computer to the drive plugged into the Wii via Samba, or delete files I am no longer using without having to unplug the drive and physically transfer it everytime. Does something like this already exist?

You can do all you described in WiiXplorer [wiibrew.org]

Sweetness! Ill check it out, thank you.