Mark Welsh, owner of the 16-9 site and designer/distributor of the adapters, is a forum regular over on Miranda's site and DPR. He's been on a quest for the best WA's for his Canon gear and took it upon himself to design the first Nikon G to EOS adapter with aperture control just so he could use the Nikon 14-24 f/2.8. The adapters come in two flavors: without an aperture lever (you rotate the lens in the adapter to change the aperture), which is shipping first for about $130, if I recall correctly, and a more expensive version with an aperture lever which will soon be available. I have a lever-less adapter on the way so I can try a Nikon 14-24 on my 5D (I'm currently enjoying a Sigma 12-24 but would like better IQ). A number of other Miranda site regulars have had an opportunity to try the lever-less adapter and had favorable reviews. I'd be happy to post my thoughts on both the adapter and 14-24 when they land here in Juneau (soon, I hope).
FWIW, altho Mark is selling the adapters, his glowing review of the 14-24 has been backed up by others. I don't get a sense of his findings being at all self serving (as others have suggested). In fact, in a recent post on Miranda's site, Mark notes that at 14-17, ghosting can become an issue with the lens due to the front element extending when zoomed out, thus protruding out from the protection of the built in lens shade. So, looks like all is not completely rosey with the lens and Mark has pointed this out.
Anyway, I look forward to trying out both the adapter and lens.
Cheers!