Intel does have a very precise binning procedure, and they'll certainly put higher-binned chips into the "2700k" box, but keep in mind that the higher binning is no guarantee of a long-term stable overclock for end users on a 2700k vs a 2600k. It would be an enormous waste of energy for intel to run ibt/linx/etc for 24 hrs, much less use a chip like we do over a period of weeks/months/years. And even then, everybody's usage pattern is different. I run DC 24/7, but many of my friends game for an hour or three per day and leave the computer off or in sleep mode otherwise. The best that we can hope for with a new chip like 2700k on the same old stepping is a reasonable assumption that an extreme overclocker will, on average, gain an extra 50-100mhz at the absolute top end, which may or may not be long-term stable.
edit: anybody have a solid release date on 2700k? I'm hoping that 2600k will drop a bit, maybe I'll be able to get one of those instead of settling for 2500k if the price drops enough.