I honestly dont see the point....
5820k $300 4.3-4.5Ghz 6 core. 25.8-27/300 = 0.086 - 0.09
5960x $1000 4.3-4.5Ghz 8 core. 34.4-36/1000 = 0.034 - 0.036
2699 ~$4000 2.3Ghz 18 core. 41.4/4000 = 0.01035
Obviously the 5820k takes the cake in performance per dollar, about 9x as much performance per dollar as the 2699 v3.
Fast and rough math says a 5960x at 4.5Ghz has about 87% of the processing power in applications optimized for up to 18 cores/36 threads, the 5960x will tie it in anything that is optimized for up to 16 cores, and the 5960x will beat it for anything optimized for 15 cores or less. Not to mention some programs are core limited by liscense, and need volume license limits to run on more than a certain number of cores.....
So in the majority of applications I would say the 5960x at 4.3-4.5Ghz will be faster than the 18 core 2699. Not worth the extra 3k to be slower most of the time imo. Since the top of the line xeon will usually be slower than the i7, I dont see much point in using a lesser model that still costs more than the 5960x.