They sell them on ebay, but I would't recommend the universal ones with the oblong holes. They slide around when you mount them. Look for the ones with round holes, and as Huey said, don't go too thick - you have to have enough threads in order for your lug nuts to bite properly.
SOLD: 2006 Commander 4x4, Bright Silver Metallic with Medium Slate Gray, CPP 28U, VES, TTG IV, QDII, 4.7L, Rear AC, UConnect, Hulk Wheels
MODIFICATIONS: P255/65R17 Wrangler SA, Chrome Tow Hooks, 4.7L Badge, Black Grill w/Mopar Grill Guard, All LTD Chrome, LTD Exterior App Pkg, Mopar Molded Mud & Taillamp Guards, Woodview English Burlwood Molded Dash, Dk Slate Gray Leather Console Lid and E-brake Handle, Kicker/Infinity, NAVUS, Bilstein Shocks, aFe cai, Nokya HyperYellow Fogs, Rear Fogs