For whatever reason, this is a huge problem right now. In the SF area, Faultline is closing down for lack of sufficient numbers (and I hear word that Bufflehead may be doing the same) and the Rats have just shed a good fraction of their number. I was chatting w. Jane (Hecht, former fore of Mayfield - they just closed up last year after 20+ years) several months ago about this very issue and apparently this is a fairly widespread problem of late.

You've already tapped the student pool (and found the associated limitations). Have you tried local ECD & Contra communities? Danceouts at places like ren faires and farmers markets sometimes draw interest. I don't have any homerun suggestions for you though (if I did I'd have managed to keep Faultline alive). Persevere as best you can and wait for the social pendulum to swing back our way again.

Right now, with the economy how it is, your best bet is to look close to home. Find people with related interests - various types of dance, history, English traditions and things like that. And don't make them drive too far to get to practice.