I don't have a method in place at the moment, but it might be possible to set up an rsync drop box here where you can upload (but not download!) files. I need to carefully consider technical, security, and legal issues before implementing this (TDE servers are in the USA, land of the DMCA and similar) but if you would be willing to use rsync this might be possible.
Tim
Would a server in iceland be of any help for stuff like these? I'm going to purchase this http://www.edis.at/en/server/linux-vserver/iceland/vrs-basic/ for my private usage. There would be quite some space left on it :-)
Nik