The mechanical linkage steering thing is an urban myth. Someone posted a $500 bounty on Pirate4x4 a few years ago, offered to anyone that could cite where fully hydraulic steering is illegal, or that a mechanical linkage between the steering wheel and the front wheels is required. If you think about it, a hydraulic failure is no more or less likely than a mechanical failure. I wouldn't hesitate to build and drive a vehicle with fully hydraulic hydraulic steering. I've actually been thinking that I might go full-hydro on my Deuce instead of trying to adapt some other type of power steering off a 5-ton or whatever. None of this is really related to rear-steer, except to say that I don't see what the problem would be.