Scarebird Brakes offers some dual pattern rotors that would probably be worth looking into. Also, there's a thread on here from a ways back where someone was taking A body 8-1/4s and had Moser cut 8-3/4 axles to 27 spline and installing 8-3/4 / Dana 60 housing ends. I do know a 2000 Durango rear axle measures 42 inches across the spring perches that are on the bottom of the axle so it fits wonderfully with the 3/4 inch advertised inset spring hangers and offset shackles. The axle tubes are about a 8 inches too far past the spring perches but you use custom length axles and can inset them so the backing plate or caliper brackets are close to the springs and use 3-3/4 inch to 4 inch wheel backspacing. It's worth hanging on, but it seems like it's also a 29 spline unit.