This might be completely off the wall or it might help someone else as well. I also don't know if it can realistically be done.
I would like a way to control an FTP client on the WDTV box from the web interface. In other words, I would be able to tell it which server to connect to, then browse the folders on that server, and tell the box to download certain files to a USB hard drive that is attached to the box.
My end goal would be that I could access the webend from my WDTV when I'm away from home through my phone, tablet, etc. From there I could tell the WDTV to download certain files from the FTP server so that they would be ready when I got home.
My current solution for this is remoting into my home PC and downloading them that way then either copying them to the USB hard drive by plugging it in, or by FTPing the files over from PC to the WDTV box using the built in FTP server in WDLXTV firmware. What I'm proposing would cut out needing the home PC running all the time.
Again, this might be a completely fringe case and if so, feel free to tell me how crazy I am. However, if its something that other people might be interested in, perhaps we could get someone interested in developing it.