Hey Andrew,
I think you need 2 people - one marketing person and one developer. It's going to be hard to find someone who has killer technical skills and also gets how to do the SEO/online marketing that you need. Plus 3-person founding teams are the strongest.
I wish you were looking for a concept (and wanted to be part of my team) rather than had your own ideas and were willing to come to DC. You sound like a great person to work with. Good luck!