I don't really mean one that's already in existence, I mean what criteria would it have to meet for your to consider it 'unbiased'? Has there ever been such a thing?
I judge bias in two ways. First the number of stories reported. Second the positive versus negative content of those stories. I have never seen a completely unbiased news source and this is why it is necessary to check stories through a variety of sources if you wish to get a complete picture of any issue. My criteria to consider unbiased would be if they report the facts and only facts. Anything else is editorial comment and should never be included in what is deemed news content.
There are none. That is why I watch/read news from several sources and form my own opinions. If all you watch is CNN, you will most love obama. If all you watch is Fox News, you will most likely hate obama. Watch both and you get somewhat of a balance.