My friends and I started a stoneblock 2 SMP about 2 weeks ago, and I happened upon a curious little thing--Withering souls have an emc value of 2,048, and 3 of them can be crafted into 3 wither skeleton skulls with an emc value of 49,152 each. This means for absolutely no effort whatsoever, you get a net positive emc yield of 47,110 emc. Needless to say this is infiniely useful and repeatable, and the lack of late Project EX emc generators implies this is not an intended course of action for emc generation and is wholly unbalanced.