Since the Blue Diamond joint venture ended in 2015 they probably haven't. They use to put cummins and cats in them with spicer, fuller, or allison transmissions(big ones). Now they only put the ford diesel/gasser and the ford 10 speed ****** so they wont have the ability to pull the higher gross weight.
I am not sure if to get the second rear axle if the outfitters did it? Or they did it in the factory. The blue diamond truck factory also made the 4000 series internationals and they shared a lot of the frames/axles but not engines or cabs. And you could certainly order an 4400 as a tandems.
The trucks I saw were set up for pulling steel coils and had minimal equipment to get 3 coils where most semis would scale out. They had one drive axle, a dead axle with duals, a 40 gal tank, and even the passenger seat wasn't ordered. They didn't last long but the extra coil per trip made it worth it. Those trucks are wore out now and the company is using T370 KW with aluminum frames and set up similarly.
GM made several pickup cab based light tractors at one time as well.