This was just seen at SEMA 2013, just in case you missed.
I was thinking you may be able to adapt the fender flares from the new Revell Jeep issue?
I built one of the original Chees Cast resin Bronco kits way back and found that one side was not the same height as the other and the wheel wells did not match up. Maybe this was fixed in subsequent copies? I made mine a custom street version, slightly lowered, with rear wheel drive and used the complete drive train from the IMC Mustang including engine (289?) and most suspension. Everything just fell in place! I sold this kit and cannot find the pics from way back. I love early Broncos.