Best Idiot-Proof Windows FTP Client

Scenario: you have an FTP server. You want someone who isn't very good at computers who is on Windows to upload something to that server.

Most of the Windows FTP clients I've seen are quite complicated. I saw a screenshot earlier of one with something like 200 UI elements. It's a headache for geeks to use, let alone newbies/"normal people". Personally, when I use Windows, I use WinSCP – but I'm not the target audience here.

Is there any simple FTP client available that the non-geek can use without needing to RTFM and without too much hand-holding? Or even better, is there a way of customising an existing open source FTP client so it can be distributed as a single-use uploader – preloaded with the server and username, so all they have to do is to type in a password, choose the file(s) and it uploads to a preset destination? Anyone know how difficult it would be to create such a thing (as per hacker standards of laziness)? (Think something like the Flickr Uploader but for FTP.)