Ok, so I have a curl/awk one-liner that can get me my ip in shell scripts that uses checkip.dyndns.org. It's super simple because the results are super simple from checkip. Anyone want to take a stab at this for google's result page?
curl --silent 'http://www.google.com/search?q=what+is+my+ip' | sed 's/.*Client IP address: //;s/).*//;q'
Google responds with HTTP error 403 (Forbidden), but it just so happens the client IP address is in the error page.