These two posts from actual successes building more gender balanced tech conferences will give a better perspective on the core issue (gender and ethnic diversity):

"Beating the Odds — How We got 25% Women Speakers for JSConf EU 2012" http://2012.jsconf.eu/2012/09/17/beating-the-odds-how-we-got...

They were themselves inspired by:

"How I Got 50% Women Speakers at My Tech Conference" http://geekfeminism.org/2012/05/21/how-i-got-50-women-speake...

To summarize, it takes lot of effort and thought. But it's totally doable with outreach + anonymization.