I'm curious if, from your example, you are creating separate identity files for each host.  I imagine not, but it's a possibility I'd never considered before.  I suppose it doesn't provide that much more security insofar as if someone can read one of your private keys from .ssh/ they can read all of them.  But it does make me think.

For my part I have this ruby script to run ssh w/ shorthands to the different identities and accounts in our internal machines.  This show is prompting me to do it the right way.  (especially insofar as it will work with scp, sftp, and scripts that use them)

Thanks for the show.  I'm enjoying that people are starting break open the tools other than the "blade" in this ssh swiss army knife.