Today I had issues with establishing a connection to a Git server through SSH. I found out, that it is possible to trick Git to use a SOCKS proxy for SSH traffic. All you need to to is, setting an environment variable:
$ export GIT_SSH_COMMAND='ssh -o ProxyCommand="netcat -X 5 -x SERVER:PORT %h %p"'
On debian the package
openbsd-netcat is required, since the traditional netcat does not support SOCKS.