While their chips aren't called EX or EP, they do have the E3 and E5 series which include six and eight core versions. I don't know if you're just unaware of those or if you think there's some reason those wouldn't be appropriate for MP?
Besides having chips that are perfectly fine for MP, an update is way overdue for the sake of USB3, TB, and especially SATA III.
I have to agree with the other responses, just puzzled why this article from April is popping up now and what relevance it has. The chips are there (and yes, Intel did take their sweet time releasing a real update appropriate for MP), nowhere to place the blame other than Apple this time around.
EDIT: My bad, looks like the E5-26xx models are EP chips (although I don't really see much of a difference from the EN versions, is it just a bit higher clock speed?).
Really all that Apple is missing out on is 10 core chips, and Intel has already had those out in previous generations without Apple using them. And I wouldn't even count on Apple using the 10 core versions next year if and when they finally update, especially if they require socket 1567.