My guess is it's not coming. The GS4 will be out sooner than they could make money off of it, if it was. Bummer.
Yes, I know it will fit in my old GS2 dock, and others, but it does not fit well. It creaks and makes cracking noises when I pop it in. Just a matter of time before it breaks.
Yes, I know there are universal mounts. I want the real thing, made for this phone.

For a lousy buck's worth of plastic, I would've gladly paid $30 - $40 for it.