Fred, if you find some 6" rims in most any size 15,16, etc. then a wheel place can put centers in them at whatever backspacing you need. In Dallas we used to have Southwest Wheel build our wheels from scratch with whatever rim and center we wanted. At the time it wasn't terribly pricey but who knows now. Used to buy alot from Nance Speed Equipment in Wichita when younger and into circle tracking.
