A kickstarter for social change projects
Similar to kickstarter, where anyone can submit ideas and projects for public donation. This is different to traditional NPO donations as this is more organic and individual. The ideas can have a larger flexibility and more personal touch.
Graceful Sadie commented
Do none of these fit the bill? http://www.memeshift.com/2011/01/19/10-online-fundraising-platforms-for-non-profits-creative-projects/