Do ypu have a Northern Tool store nearby??--if not they sell axles pretty cheap thru their website or catalog,shipping might kill the savings though...
We sold just about every FWD rear axle that came into the junkyard to build it yourselfers,they used them for utility trailers and lawn tractor carts to haul wood,mulch,etc...the Caravan ones are pretty strong,but I dont think I'd trust them on a car trailer or skid steer hauler!..
We built 2 car trailers using caddy Eldorado/Olds Toronado rear axles,they were dead axle but still worked very well for our purposes,(scrapping stuff and hauling a vehicle home after buying it,or a car to the race track)...one guy boiught a 1972 Eldorado from the junkyard and he grafted a car trailer to it--he saw one in Hot Rod magazine someone built into a car hauler by cutting the car off just behind the front seat and grafting the car trailer to it...it was a "low rider: and the 455 engine hauled anything that fit on it pretty wasily and it still drove and handled nice--was a very cool rig for hauling his drag car to the speedways...