Here's a little surprise. I just got my 4S today, and I've been looking into a dock/hub to use Continuum. Trying to decide if what I want. Just for fun I opened the Continuum App and streamed it to my Roku TV. Works great. I realize this isn't going to be an ultimate solution but.... I can see it's uses.
More on topic. I think I'm going to go with the Display Dock. Most of the third party hubs would make it a little hard to use the phone without some sort of USB C extension cable.