Nikon has already released their first HD movie on Youtube.
can record directly to uncompressed Apple ProRes 422 and start editing immediately. Of course, the problem is that many camera manufactures are already switching to 4K resolution like the Red Scarlet and the Canon C300. And since the 5D Mark III hasn't been revealed yet, you can pretty much bet the farm that the 5D Mark III will likewise have uncompressed HDMI recording.
The lesson here? Don't buy Nikon unless you already own all their lenses.