[gunapologist99]

Userify would have made that pretty painless (all it really seems to do is update the authorized_keys across all of your servers every minute or so)

[superq]

also userify allows you to set up sudo access on some of the servers and not others, so that'd take care of the other root-access issue you have. (sudo also provides auditing/logging controls that are useful in a multi-user environment)