After posting this, I wasn't able to get a good answer from dell sales as to if it was compatible with the new macbook. So I decided to place an order and experiment for myself. The dock just showed up today, but I've played around with it and haven't had much success. The macbook seems to recognize all the ports in the docking station, and upon checking display properties, it was even able to identify the monitor I had attached to it, but I couldn't get any display output with any resolution or refresh rate I tried from either the displayport or hdmi connections.
My experience with Dell support was horrible for this product. I tried calling support just to see if they could give me an 'official' answer on macbook compatibility. Even though I don't expect them to support the macbook, I figure I can't have been the first person to try this and there has to be someone at dell that knows if the two products are compatible or not. Getting to the right department was impossible. No one could find the service tag in their database. I kept getting tossed back and forth between departments from sales to customer support to tech support. Apparently there's no tech support department that deals specifically with docking stations... everyone I talked to wanted to know what computer I was using it with so they could transfer me to that support department. Any of these computer-specific departments didn't want to answer dock questions until they knew what computer i was using, and immediately upon hearing I wasn't using one of their computers they wanted to pass the buck to another department. I could have pretended I was a Latitude user and asked about mac compatibility "for a friend" but I don't feel this should be necessary to get someone to answer general questions about a product. It's clear that Dell support doesn't treat this product as anything beyond an accessory for specific machines of theirs (even though at CES they promoted it otherwise).
I've initiated a return... I guess I'll just wait for the Caldigit dock to become available.