what about a file share on a server in the office ???
or if for some reason you need to hide the location / provide some security then a desktop app that copies the files and you can rename them , encript them or whatever...
a simple login profile can map a share so the user gets a pre-set drive letter to drop the files into.
a really simple client app could be a "Drop Target" and use the current loggin of the user in the domain to then create the file on the server with some permissions, folder name and file name generated by the app.
but only use an app if a simple copy will not work.