You're not going to get that. If there is no way to keep bozos out, there is no guarantee of quality, and thus less interest. So just stick to fun meetings once in a while, rather than anything smacking of an 'organization'.
Get a techcrunch posting and also start rumors that your demo day has change the world startups with amazing profit potencial. Get 20/30 people just to go around places and just mention it in a offhand way.
