More options for SSH connection

[pmarek]

I need to use a machine as gateway; currently this is done via a

ProxyCommand ssh user@host netcat %h %p

in my ~/.ssh/config.
This works fine for openssh and xpra, but winswitch doesn't use this information (yet).

A similar mechanism would be nice; or, at least, some kind of (pre-)connect command that can build the first hop.

Furthermore, I currently use a TCP remote-port forwarding to get some actions tunneled back; it would be nice if either this, or some other notification mechanism (sending strings) could be done over the same channel.