This extension displays different mouse cursors than the default depending on what part of the scrollbar the cursor is hovering. It is primarily designed for use with thin scrollbars in order to provide better visual feedback.
Note: Changes to scrollbar elements may not take effect until the page/window element to which the scrollbar is attached is reloaded. Some browser chrome elements reload automatically; most page elements do not, therefore they'll need to be reloaded manually. (So, while this extension is restartless, you will probably need to reload any already opened pages before you see any change to your cursors.)
Trivia: The name of this extension derives from my Elegant Scrollbars style at userstyles.org. The style is "elegant" in that it uses no images to define plain, basic scrollbars that are thin and functional using any colors preferred by the user. The code used here for displaying alternate cursors was simply extracted from that style. The cursors are not themselves anything I would call elegant; they're just the cursors provided by your platform.