This is quite an old thread, but I thought I'd post a quick reply as I just had the same question myself and found an alternative solution.
Some of the guys who manage our blog platforms were frustrated that without pre-moderation they didn't have a clear list of new comments, and had to scroll through all the blog articles hunting for new comments. One really simple way to check for any unread messages at any category level, whether you're moderator or not, is to simply use:
http://[yourcommunity]/t5/forums/unreadpostspage/category-id/[yourcategory]/post-type/thread/tab/message
Not exactly what the OP was asking for, but maybe it'll help someone at some point. :)
