[opinali]

Don't worry about that single time you've been (mis)contacted, recruiters are really a hit-and-miss even at Google. Your best shot is being referred by a Googler. You claim to have significant activity in the community and OSS projects so it shouldn't be hard to find Google engineers that have some familiarity with your skills. If you are a strong candidate, it's a win-win since whoever referred you gets a nice bonus if you get an offer and accept it. Once that happens you have the same challenge of resume/interviews as everyone else, the advantage of a good referral is mostly to get over the unintended barrier of recruiters' skills and time to find good candidates.