This is exactly why I started the project also I know there are hit pieces that are coordinated between the news-sites. I wonder how much other news that is reported is also coordinated reporting. However I have no direct proof of this and I cannot start from trying to prove something that I suspect. First I need to collect and analyse data fairly.
So far I've just used newspaper to do the hard work of scraping for me (https://github.com/codelucas/newspaper) some basic filtering techniques e.g. I discard everything that has a question mark at the end of it (Betteridge's law of headlines and an MySQL to store articles etc. Then I run the second script to do some basic string analysis. I am going to be building a small web app to display the results.
So far it is early days (It about 4 or 5 python files and a config file) and I have got two other projects I am working on that probably need completing first.
There is a more serious underlying problem you've spotted, which is "jounalism as stenography". Lots of people can put out press releases, which then really do get copy-pasted into articles. Same with "wire copy" sourced from AP or Reuters. This can be abused by bad actors to get obvious or difficult-to-refute falsehoods into the public memetic consciousness by repeating them.