You can save data to a path on the filesystem, so one way to do this is with a network mount. Lots of academic departments have their own GPU clusters, and they tend to have a shared network filesystem.
We want to have more ways to do this though. We were close to adding SFTP support, but didn't get round to it. Another method could be to implement our own server, but we're trying to keep it simple for now. I'd be curious to hear your feedback here: https://github.com/replicate/replicate/issues/366