Do you plan on running ag tires on the highway, at highway speeds? Good luck, I can barely stand to drive a tractor because they are so unbalanced and anti highway. Save some money and 1ton it... If you find the right old guy with an old farm truck you can easily find them for the price of the locker. Weld them up and forget about it.
EDIT= Im part purist, but I can only imagine the pain those 4cyl axles are going through. You could market the rear axle and pay for one of the 1tons. Part out the front end and call it done money wise.