That's not what he's asking for. He's wanting to have this setting be change-able at the channel level, while your solution is to disable it completely for all channels.
The only way I know to do this is to have a script to trap all messages. If it's not in an "unimportant" channel, then it returns without doing anything. But if it is in an "unimportant" channel, then you send an echo with the -n flag in order to prevent any highlighting of the switchbar icon. I've tried several times to post example code of how to do this, but it seems to keep triggering a server crash. When I preview my post with the code, the Preview Post fails, but when i remove the code then preview works just fine. I'll have to try it later.
