Kinda of topic but not really.
Spidertrax uses modifed F450 unit bearings for their front and rear spider 9 kits. these unit bearsing use drive flanges or locking hubs in the front and full float rears, with 5 on 5.5 bolt pattern.
if spider can keep the the orignal abs sensor in the unit bearing. you could have a full float rear axle with a 5 on 5.5 bold pattern and keep your ABS.
i have been doing some light research. but i have not contacted spidertrax about it yet.