Fascinated by Joes work, I ordered a WU-1b, to hack.
I got it yesterday, and immediatly cracked it open.
It's practically identical (will try to get some good photos) inside, except for the plug, which is now a standard mini-usb plug.
I used the WMUA app for the iphone in my testing.
I can confirm that the WU-1b also works with the D800, with the same modifications joe described.
basically I only had to supply power (5V) to pin 1 to both the camera and the WU-1b, as well as 3V on pin 4 of the WU-1b.
Unfortunately I did not get it to work reliably with my D300.
At some point I did get some kind of connection, but most the times, the WU-1b only blinks red.
Will try with more cameras soon.
By the way: when you have live-view, you can focus the camera at any focus point by simply tapping on the part of the liveview image you want to focus on!