Huh? They work very well inbound, including with a password. Once you have root, just use the passwd command to set a user password and a root password. OpenSSH then uses those passwords. Dropbear should too, but I don't use it.

You can set up openssh to block root login by editing the sshd configuration file, just like on a full-size PC. It's still openssh, after all.

Finally key-based logins to and from the device work, and if you're aware of the security implications, you could set up a no-passphrase key to login to your backup machine, and use rsync over SSH that way.

rdiff-backup is also available for use, but not available in any OS2008 repositories yet. It would probably work with a manual install, but of course, no guarantees.

P.S. Fish also works inbound. Don't know of any client that can do it outbound.

P.P.S. I also cross-compiled gftp-gtk for the tablet, under OS2007. The UI is horrid - no hildonization done, etc, and it needs to be manually installed. It may work under OS2008, the tar.gz file is here