I recently published the ABC Classification article in www.daxpatterns.com, which is a more structured and organized way that recap what I already described in this blog a few years ago (see ABC Analysis in PowerPivot). The pattern describe how to implement the classification through calculated columns, so we consider it a specialization of the Static Segmentation pattern. You can implement it also as a measure, implementing a Dynamic Segmentation, and Gerhard Brueckl already described such implementation in his blog. I am not sure about creating a pattern for the dynamic version, because of the performance issue that could arise even with a few thousands of items to classify.
Any feedback on this is welcome, we already have other patterns in the working, but we can always change prioritization based on comments!