Multiple login methods: FB, Twitter, blogs – or register

I’m looking for a solution to allow comments from

– people with a valid FB account
– people with a valid Twitter account
– people with a valid blog of their own
– people who have registered as a reader of the blog.

If the reader doesn’t meet any of these requirements, they should be offered a chance to register.

I’ve been searching through the plugin directories but haven’t found anything close to this. Is it out there?

I’m starting a new blog afresh with no plugins installed, apart from Akismet.

The point is to disallow fully anonymous comments but to make the commenting as simple as possible without the trouble of registration.