Fantastic post. I would note, though, that OkCupid reduces your 9-192 years down to about 9 seconds. You can simply do a keyword search for Unicorn to immediately bring up all the people who identify as unicorns. Moreover, you can set all your filters to exactly what you and your partner both want. In cities where the OkCupid population is dense enough (Seattle, NYC, Boston, DC, SF, among others), it shouldn't take more than 5 minutes of effort to find a proper unicorn :)

Getting the unicorns to reply to you, though, is a different task entirely, and may require that you understand the ins and outs of online dating (good profile, good photos, good first message, etc.).