Upload & Sell: Off
Last conversation I had with CPS was its officially only announced as "an intention to build" and at this stage there is not even a working sample made only mock ups, so dont hold your breath.
In the meantime, you could always buy a Nikon 200-400 f4.
I looked into that a few years ago when the 1Ds II was the best Canon and there was no FX Nikon yet. At the time one person wanted $5000-7000 for the conversion to EF, not including the 200-400/4 Nikkor.