When you first store something in content repository, CR will create an "item" (identified by the item_id) and a first "revision" (identified by revision_id) of that item. Successive versions/revisions of the same item will have the same item_id, but different revision_id's. Now items and revisions are all objects, and thus have their own creation_user entry in acs_objects. Each revision need not have the same creation_user, or have the creation_user of the item it belongs to (e.g. in you case Randy, where the site admin is the creation_user of the edited article because (s)he was the one who uploaded the edited article).
Now if I understand correctly the feature that you want, the CR datamodel should already accomodate this. The creation_user of the item (and the first version, naturally) is the "originating author", but each successive edit (i.e., a new revision uploaded) will be owned by the person who edited and uploaded the new version. So to implement the feature, it is a matter of getting from the database the creation_user of the item whenever you get the the creation_user of the revision to be displayed, and instead of having just an "author", you report the former (creation_user of object with item_id) as the "originating user" and give the latter (creation_user of object with revision_id) the "edited by" credit. Change a few queries, and a few templates, and you're set.