In my local supermarket they label those as "Beef Back Ribs." They're not hard to find around here as they're a by product of stores creating boneless rib roasts and rib steaks, but most of the stores cut them into individual ribs for some unknown reason. So, what's hard to find is a rack of beef ribs. I snap them up whenever I find a whole rack. Short ribs are also quite common around here, but the beef back ribs have a more fatty, rich flavor IMO. I love to cook beef back ribs on my PBC. I throw some of the beef & game rub on them and then I'll sauce them up with some Sweet Baby Ray's Hickory Brown Sugar at the end.
Enjoy!