Palliser,
Thanks for all your awesome work you are doing on the Arduino Due - Your idea on the wedge is nothing short of awesome! I will be super impressed to see it in action. I'm quite frustrated with the slowness of all of the WIZnet (W5100, W5200) options for Arduino Ethernet capability and I'm down to help test a faster and more reliable solution for the Due.
I just ordered a couple of the TaijiDUE boards and I'll open up both of my Arduino Due's to sacrifice for this project in the meantime since it should take a couple weeks to get them in the USA from where they ship in China.
I also noticed there were several PHY options listed in the following document:
http://www.atmel.com/Images/doc11153.pdf
Are you choosing the Davicom PHY due to it being part of the SAM3X-EK evaluation board from Atmel?
If so, I'll be ordering some of the Davicom PHY as well as a couple of the others just in case we need them on hand for testing.