This last weekend I played a lot and in doing so I got a lot of tells. So here's what I did.

Turn the Chime sound off for when you get tells, Turn on the tells filter for General Tab (main chat) and then put tells in Event Tab.

So when you get a tell it won't ding. And the Event Tab will be green when you have a new tell.

Is this for everyone? No! But if you're tired of waiting for a real solution to the problem, this is the best thing I've found. If you're a chatty person this probably isn't for you.