This may seem lame, but back a few years.. a guy in my squad in the air force bought a system from "Don Lapre" at least I think that is his name. He kept hawking something saying "with one tiny classified ad", yadda yadda.
I remember laughing at first, but I looked at the info he had on how to place ads in papers. I used it and it worked for REI.
I don't have it anymore, but if you could get your hands on that info, while it might be outdated, it would be a great place to start.
One medium worth considering would be craigslist. Even though there is the ongoing debacle about scams and scammer rings, it is still a high traffic place that could lead to some leads.
I'd consider advertising in some of the High-End Magazines out there for "Rich Folk" . . . Forbes, Hamptons Magazine, Beverly Hills 213 Magazine, etc. Maybe you could better target the top demographic with those resources?
Many people don’t know this but Google Adwords now allows you to post print advertisements, and radio advertisements anywhere in the nation. You can send out ads very quickly.