So, been doing a bit more thinking about the rear tire rack. If I was to do something like the truck in post #26 would you guys think a good starting point would be a forklift mast? Essentially it is similar, though opposite (extends down not up so would need some rework). There is a place within driving distance that sells used forklift parts and I can get the mast at what seems a reasonable cost. Could possibly solve the sliding portion of that rack.