John here, from rsync.net.

We don't do any of the things you list - not even close - and we don't ever plan to.

We can, however, do this:

  pg_dump -U postgres db | ssh user@rsync.net "dd of=db_dump"

and this:

  ssh user@rsync.net s3cmd get s3://rsynctest/mscdex.exe

... it's probably not for you. Cheers!