Lamb back ribs are a problem. Baby back ribs were born from the desire to have boneless pork loin roasts, with the rib racks being a byproduct. Beef rib racks are a byproduct of boneless beef rib roasts. But there's not much demand for boneless lamb rib chops or roasts.
Check the ethnic markets like Jons on Vermont, Super King on San Fernando Rd near the 2 fwy or some of the other ethnic markets. Lamb is usually cheaper at these places. Good luck and use plenty of garlic and rosemary!
Yes, they were the ribs I had from Jack Stack's BBQ. However, they charge a premium ($60-80 for 2 racks) and I was hoping to make them a little cheaper. I'm not sure what riblets look like. The ones I'm looking for are about the size of a baby back rib.