Not exactly, but Reporterist is a very interesting idea. In short, it's a service that connects freelance journalists who have stories to sell, with editors at publications who want to buy content. If an editor wants to buy a story, the two can haggle on fees (or, the reporter can set a fee). It also puts the power in freelancers' hands, as they can line up a variety of publications to which they want to pitch. If one publication passes, the pitch could go to the next one on the list.
I don't know how many other similar services exist, but I do know that this is exactly what sites like MediaBistro do not provide. Bistro, as successful and useful as it is, provides just about everything else: how-to-pitch advice, forums for writers to discuss freelancing headaches, resume and portfolio services, etc. As far as I know the site doesn't help make that final link, however, between freelancer and editor.
In this article with OJR.org, Reporterist founder Sindya Bhanoo says they've talked to many editors and that this service is needed in news departments that are looking for ways to get good original content from a variety of sources, and sometimes on the cheap. It'd be nice if more editors were willing to adopt this. As someone who has unsuccessfully pitched magazines, the waiting game can be painful for both ego and wallet.
Then, there's also a citizen journalism angle and some grand thinking behind the site.:
Bhanoo: A lot of sites are opening up to citizen journalism. But we're trying to create a place where journalists and up-and-coming citizen journalists can sell their work and start building a reputation.
Our larger vision is that it's the next generation wire service, like an AP or a Reuters. The public wants high quality, relevant news. As the industry's cutting back, a lot of regions are under-covered. Most of the editors we spoke to say they're relying too much on AP or Reuters content. At Reporterist, they will be able to look at all these stories and sort them by region or topic. Our vision is to be a wire service for local, topical news.
It'll be interesting to see how well the site does. Perhaps it'll motivate me to write something up and give it a whirl myself.