Only thing now that actually does that is lockinfo,
i'm not sure but intelliscreenx might do that too, try it out (3 day trial)
but both of these tweaks, are on the heavy side, there are no light tweaks to collapse sections
I know you're waiting for a tweak just for collapsible notification but LockInfo is soo worth it. Besides the collapsible notifications, two features I absolutely LOVE are the statusbar icons for notifications and the ability to view future appointments ahead of time (have mine set for one week ahead) instead of just 24 hours in advance.