IRC really isn't a bad idea. It's my experience that a lot of the help/support channels there have everyone set to NOT be able to talk upon entrance - you gotta wait until you receive +voice to ask your question and then a mod can PM you and fix your problem there rather than in the main chat window. If a problem like what we had this last weekend happens again, a message can be triggered to automatically hit the IRC channel at regular intervals - like "Forumer is aware of the <blank> issue and technicians are currently working on solving the problem. Please be patient." You get the idea. That would give people a sense of an immediate reply.
And once a channel has the X bot (that's the one I'm most familiar with on the Undernet IRC network), it really doesn't HAVE to be monitored 24/7 by a staff member.
I am familiar with Teamspeak to a certain degree and can just hear 400 people all clamoring for an explanation to a problem/bug/issue at once
...neat idea, but imho, I just don't think it's feasible.