make ssh-add conditional?

[openssh at yarra.no-ip.org]

Hi folks, I don't know if this has been suggested and knocked back before - I 
didn't find it while googling. Anyway, I'd like ssh-add to have an option to 
add a key only if it is not already present in ssh-agent. I currently use a 
shell function to conditionally add a key, then login to a remote host:

go ()
{
    ssh-add -L | grep -q 'id_rsa_mykey$';
    if [ $? -eq 0 ]; then
        echo "my key already present";
    else
        ssh-add ~/.ssh/id_rsa_mykey;
    fi;
    if [ $? -eq 0 ]; then
        ssh myhost;
    else
        echo "Oopsie";
    fi
}

It works well enough, but it seems inelegant - I'd prefer if ssh-add had this 
built-in already, so I could do something like:

go()
{
	ssh-add ~/.ssh/id_rsa_mykey && ssh myhost
}

...and ssh-add would not ask me for the passphrase if the key was already 
present, and exit 0.

Is it feasible? Would it be useful? If I make a patch for it, would it stand a 
chance of being accepted?

Regards, Philip.