I actually secretly sampled a system like you guys are suggesting two years ago using a modified version of the Advanced Post Reporting System hack. The system would automatically send PMs when the status of an "issue" (in our case judgment) changed. Results were mixed. My sample judges often either forgot to update the system or too little time passed between updates (meaning they'd click "assigned" the day they completed the judgment), rendering it largely useless to players. The other downside is that it literally took over the post reporting system, meaning players couldn't report spam or inappropriate content. That doesn't mean a new system couldn't be created, it's just that I would prefer not to use the old one. I've attached a screen shot of what a player would see if looking at the system to this thread. It definitely looked cool.
Ultimately, I decided to give a variety of different judging methods with some fixed (but conservative) timeframes for judging. Giving you guys the freedom to determine the depth of review has definitely reduced pressure on our volunteer judges. Realistically though, I don't see a progress report system being particularly viable. Drum, every judge has a different process, so other judges might not update at the same things as you (I rarely re-read threads, for example). PMs are nice, but I wouldn't want to add anything that isn't automated. Argue they are easy all you want, but frankly I want judges focusing on judging rather than administrative matters. That's why I created the Head Judge position, after all. Matt, a general site counter is a cool idea, but I envision most people would submit a ton of full judgments when they saw the queue was low, ultimately resulting in a perpetual queue. Sorry guys!