I was speaking to Darren ( I think).. at Autofab yesterday about a hub upgrade for 7/8” kingpins, which they sell but dont have on their site, and he seemed very knowledgeable with the setup and made it seem like the weaklink will be the kingpin bushings in the beam end, and they will just be a maintenance item like wheel bearings... I would say cut the radius arms off and make them bolt on to the beam, you should even be able to use the old rad arms and just weld a big piece of tube to the end to slide a bolt through with some tabs on the back of the beam. Then mount the rad arms wherever you want to the frame. Seems like the quickest cheapest way.
I do agree on the beams though. Probably the easiest and cheapest way.. kind of bummed about cutting them up though i dont want it to look like an afterthought. These beams have a ton of plating on them.