The System Preference > Appearance > Number of recent items > Document setting is all-or-nothing.
Is the a way to [allow|prevent] additions to the Documents list based [File extension|Application|Kind]?
I might want Word documents to be in the list, but not images. Or allow VLC to include files, but not Xee.
An AppleScript would probably make sense.
** edit ** Tiptoe is a potential solution.