Excerpt/Summary for Everyone but Full Post Only for Registered?

hey all– i’d like to restrict full post view access to certain posts (not all in a category) to registered users, but allow all readers to see either the excerpt and/or post up until the more >>.

the goal is to require a reader’s email address to read some full posts or download certain mp3s, contained in the latter part of a given post. ideally, a message would appear in the rss feed directing users to the site to register/log in to view the full post.

from my cursory look at existing restriction plugins, it seemed like restricted posts become totally invisible to unregistered readers. i def. don’t want this — just like a newspaper site, i’d like a summary to tease people to register.

anyone know if this outcome is possible?

a hack/workaround might be only implementing user level restriction on single.php, if this is possible. anyone know? the result would be everything up until the more >> on the index and archive pages, and a message instructing readers to register/log in on the single post page.

another approach would be to use wordpress’ post password protection feature i guess… however from what i’ve seen that also hides posts entirely, and implementation for membership purposes seems messier.

i would really appreciate any thoughts on this. thanks:>) i’m using 1.5.2 btw