Well for one.....u can't buy a regular cab 6.4 short bed....u will have to find a long bed and chop it....unless u find someone willing to part with there's....
I know they dint make one, I built one before, just hoping someone around here would know of where either a 4x4 RCSB or a RCLB 6.4 was that wasn't posted or something, I had a 6.0l 2WD and I can only imagine how a 6.4 4x4 one would run...