I had an ancient addon to alert me in the default chat log whenever a spell/heal crits, far more convenient than scrolling back through the combat log. Since FuBar_TopScoreFu is essentially doing all the same functionality I made a patch to add the functionality to it.
It alerts for every crit regardless of the top score - some screenies follow.
Example alert for a crit Frostbolt
Example alert for crit heals
'Show crits in chat log' menu option
I performed a diff between my altered version of 'r46042.1' and the original. I then tested it in-game using FuBar-r45986.