We had them three years ago....they were called Sandy Bridge-E. The unlocked version was an 8-core die neutered to 6-cores and the un-neutered 8-core version was a Xeon that was locked down hard. There should have been an 8-core premium option for Sandy Bridge-E, the i7-3980X that some jackass at Intel decided to cancel. It's likely the same jackass was responsible for hard locking the otherwise wonderful E5-2687W.
So yes, we should have had an unlocked 8-core three years ago...only Intel's refusal to provide a fully enabled unlocked option kept it from becoming reality...there were absolutely zero technical limitations.
Like I said if you think it is that easy go ahead and make some.