I just bought axles (beams) from Axis for my '78 Tradewind. Spindles sized for my '78 disc brakes, beam downrated to 3,000 lb. Shock bracket pre-mounted. Mounting holes same dimension as original. The axles bolted right in, just like original equipment.
I bought straight from Axis. Easy purchase. Easy folks to work with.
By the way, Dexter would not make their #11 beam downrated to 3,000 lb. (the #11 beam has the correct spindle size for the original 12" disc brakes)