A couple of weeks ago rumors were circulating the web that Intel had cancelled the Ivy Bridge-E in favor of a Haswell-based enthusiast platform, but now FUD Zilla claism Ivy Bridge-E is still in the works but that the chip has been delayed to Q4 2013 instead of Q3 as originaly intended.
Since Q3 starts in July, a relatively slow month for IT, the normal time to launch products is late August or September, but at this time there is no confirmation that this will happen at this time.
Sandy Bridge E, or Core i7 3960X, was launched in Q4 2011, November 14th to be precise. This can give you a clue on when to expect the successor.
Originally Ivy Bridge E was supposed to launch in Q3, one quarter after the launch of quad-core Desktop Haswell processors. Ivy Bridge E works in X79 motherboards but we do expect that a few key motherboard vendors will have their newer versions ready for the launch of the new $999 flagship processor.