Understandably, from a marketing standpoint, you don't want to plaster these things on the front page; However, having a feed on the login page outlying any issues with the site (eg the current login issues) would go a long way in creating an informed customer base. Wouldn't be hard to implement something tied to Twitter (Don't care for Twitter myself but it makes a great 3rd party site/service status updater) to save your database the extra work.
Eg I spent a good deal of time thinking the site was under high load when trying to login; however, after going through the forums, I found that it was a login issue and not a load issue. Could have saved me time to see a message right on the login screen.
It also gives your customers reassurance that you're working on or monitoring a problem without relying on them to actively seek out a thread on the forums.