Twitter and OAuth - Extending or Complimenting Existing Twitter and OAuth Modules

Drupal already has a Twitter http://drupal.org/project/twitter and OAuth http://drupal.org/project/oauth module. This request is anticipated to build on these modules' existing functionality, but I am also open to new approaches. What is needed:

1. When a user registers on a Drupal site they enter their Twitter username as the required username, authentication is done via Twitter (OAuth),
2. Whenever a user makes a comment on a node, or adds a new node, their Twitter stream (as well as the site's Twitter stream - but this functionality already exists) is updated with the title and a link to their new post and a hashtag of the site's name - ideally this should be an option in their user profile which is set on registration and can later be changed - open to suggestions on link shortening methods;
3. When a user not registered with the site makes a comment they are given the option of verifying the comment is really from them via Twitter's OAuth functionality.

My personal contact form is enabled, happy to discuss in public or private space.