I don't think there is / will be, because the idea itself is flawed and goes against the very concept what freelancing is. Actual freelancers have their reputa

I don't think there is / will be, because the idea itself is flawed and goes against the very concept what freelancing is. Actual freelancers have their reputation and local network of contacts, plus maybe some attractive online presence (blogging, open source, etc). If needed they can try reaching companies directly, circumventing platforms which otherwise would make him appear as a commodity. Remote job boards work fine, whether you are applying as a freelancer or employee. 'Middleman' platforms not so much - in the end remote work is much about trust/communication - escrow/time-tracking can be counterproductive.