I also had a look at this particular hybrid and I personally think the truck was a C30.
In the Army History Unit Workshop was a C30 chassis (Ambulance) and parked next to it was a carrier. If you remove the distance from the carrier front idler wheel to the first road wheel, as shown in the test vehicle shots, the distance is correct.
This topic has come up before. The best of many versions was a Ford Jailbar type outfit that had the full carrier tracks and road wheels fitted.
Top speed for this vehicle would be 20 - 25 mph, about 10mph slower than a normal Chev
Please build it. Maybe you could fit twin handbrakes in the cab so you can turn it.