It's an interesting idea, a way for people to seek out volunteers instead of financial backers.
However I don't think it could ride the same wave of popularity that Kickstarter has. KS works as well as it does because there are many thousands of people who browse it like a store, who are willing to drop $5-$100 on a project, to get some rewards or at least warm fuzzies. In other words they have gamified the pledging system, so that financial support happens as a byproduct of people 'upvoting' cool projects they like.
I don't know if this would work for volunteering, because it's a lot harder to make good on a commitment to volunteer than it is to authorize Amazon to charge you $20 a month from now. You also would not get as many casual backers, the kind who treat KS as a store, who want something out of a project, and are not backing projects just to support them.