On the off-topic of large file transfer, has anyone ever experimented with torrent? It suffers from the primary non-third-party disadvantage that both parties involved have to be online at the same time, but what may-or-may-not (testing required!) make it better is that, after setup, it could be run in the background with trivial pause and resume capabilities so that either party may go offline at any time for any reason and when both are online again, the download will silently resume wherever it was. Twould be effectively fire and forget à la FTP, with no servers or secondary interaction required.
Tis so far only a thought experiment of mine (in relation to sending my brother ~150 GB of data I've had backed up for him for years, for which he only recently acquired the space to keep it himself --
snail mail is the only other alternative I see for now, and that's expensive), but it seems promising to me.