In case of a full scoreboard it is not possible to retrieve the server status, since the request will stall. There is no other way to retrieve the server-status on a reserved port, or via other means.
Reclassifying as an enhancement, if the server's too busy it's too busy.
Have a look at Jeff's mod_backdoor. Don't know how well it works with 2.4 but give it a try: http://people.apache.org/~trawick/ (look for "mod_backdoor" which will find you the source and a txt file serving as a README).
Would also like to see this implemented. 1 (or configurable N) reserved thread(s) for mod_status would be extremely lightweight and helpful when the server is otherwise very busy, because the very thing you're trying to do at that moment is figure out what's hogging all the connections, but can't.