Hi! I recently searching the web for idea and I have found interesting Mac app, it`s the Storyist (http://www.storyist.com/index.php). This application have interesting features - organizer<http://www.storyist.com/features/organizer.php>- it (i hope so) can simplify browsing in different doc structure elements and adding it (bibTeX and images, and it can also include all user doc`s) by representing all of them (by cathegory) in left side of the window (not by pop-up box ;) like this happens in many apps) and last used (or notes or some similar) in right side.
Best regards, Dionisiy