indeed it has been brought up before.
limiting it to supporters is not a good choice I believe. Not everyone like chat, and chat thrives best if many people join in. Opposed to forums the messages are very temporary, so you would need at least a few people in a chan at any time, to be enjoyable.
But before something big like 24/7 chat is linked to the BB site, I think they should either get a sever to run IRC on themselves, or look for a solid and relyable server. They now use Mibbit, which is ok, but the services on Mibbit have dissapeared a few times, and when we have a lot of public using chat, we must be asured the services are up and running all the time, and if they go down, need to be brought back up within 24 hours, which just isn't the case right now...
They are not your friends; they dispise you. I am the only one you can count on. Trust me.