Put this into ~/.ssh/config where 50k is the limit for the connection.

Host server1
    Hostname server1-slow
    Port 222
    proxycommand pv -q -L 50k | nc your.host.example.com 222

An other approach could be to create an alias in ~/.bashrc which could may be look like this (untested) which of course would only work for ssh tunnels created using the ssh-slow alias:

alias ssh-slow='ssh -o "ProxyCommand pv -q -L 50k | nc your.host.example.com 222"'