I don't see them in my part of SC either. I'm 10 miles outside of Charlotte NC and I've seen only a few and those were at a store that's gone out of business. I worked in a steakhouse that shared a meat room with a small grocery store/butcher shop once back in Arkansas, and our meat cutter (this was in the 1990's) that had been an old country butcher for 40 years taught me a lot - how to break down both a shoulder and a round and the sirloin but that was a lot of beers ago and not a skill I kept. Shortloins and ribs came as packer primals but we cut roasts and sold a heaping ton of ground sirloin from the shoulders and rounds, as well as all of our roasts etc and steaks from the sirloins. I almost wish my life hadn't diverged from that path as I actually enjoyed the year I worked with him. These are the part between the round and the bottom of the sirloin if I'm not mistaken. I have never cooked one. He called them California tri tip roasts and sold them high.
