There was a company called Thompson Machinery in Thibodaux, LA (pronounced "Tib-a-doe") that bought tractors from AC without the front axles and installed their own front axle--a large arched casting to provide higher ground clearance for working in the sugar cane fields. Final drives may have also been different too, but I'm not sure--they may have installed larger diameter rims/tires. I've seen this setup on D17's, but not on any WD45's. That's not to say they don't exist--just that I haven't personally seen them. Can't address value, but the assumption would be that lower production numbers would tend to result in higher values than their factory "stock" cousins.