SSHdeploy — Update and Distribute SSH Key Files
SSH Deploy automates the process of updating all of your SSH key pairs and authorized_keys files. It takes a configuration file that contains a list of your ssh keys and the corresponding clients and servers and it then creates and distributes your ssh key pairs to the clients and your authorized_keys files to the servers.
You can find the latest version of the source code on Github.
Be aware that SSHdeploy is not recommended for use. It has some serious problems that may never be fixed.