ln -s ~/Dropbox/.shared/.ssh ~/.ssh
ln -s ~/Dropbox/.shared/.bash_profile ~/.bash_profile
chmod 700 ~/.ssh
chmod 600 ~/.ssh/id_rsa
chmod 644 ~/.ssh/id_rsa.pub
chmod 644 ~/.ssh/authorized_keys
chmod 644 ~/.ssh/known_hosts
Now you can use the same key on all machines. Boom goes the dyn-o-mite.