Dedicated teasers readable by anonymous, require access level to get to the rest of that content.

(Not sure if this is already possible through the existing ACL API.)

It would be practical if Drupal core included support for Drupal site administrators to deploy tools to implement business models for paid content (and subscriptions). Ways to "market" (parts of) the site content without giving out the crown jewels.

An example would be the possibility to manage 2 teasers, one that takes part of internal lists for users that has the privileges to access that content, and another that specifically targeted the outside world that does not have access to that content. This is somewhat relevant to the Excerpt and Node Teaser modules, but more of a question about how to facilitate such modules.

In short:
It should be possible to maintain teasers that are readable by anonymous users, and then require some access level to get to the rest of that content.

Is this already possible in Drupal 5, or is this an appropriate feature request for Drupal 6?
I think we are currently lacking an appropriate ACL setting (permission) for this in core.

Related example (forum post):
"Enabling SE access to private content"
http://drupal.org/node/143898