Sully, with a 4 series gear, that is a D60. The D61 only came with 3 series I believe, and the lowest ratio was 3.5x:1 or around there.
Corrupt, I doubt Ford would have considered the 1/2 ton D44 axle for use in the rear of their 3/4 and 1 ton vans. Especially when a diesel engine was an option in either. I've been told by people that D44s can be found under Ford 2wd 1/2 ton pickups before, but I've never seen one and it seems a little far fetched that they would have stepped down from the 9" to use a D44 in even the light duty stuff. On the other hand......we ARE talking about Ford here......so anythings possible.
The Superior Super 35 kit goes beyond D44 shaft and carrier strength. It is a very pricey kit, but it is nice quality and it includes the locker. If you are going to keep that D35 with your setup, you might as well start saving for that kit and designing a really good truss.
Rooster your right, It's not a turd I guess. It is a pretty stout axle. The added expenses and trouble with using the gear spacers, and the lack of traction aiding devices keeps it from being a first choice for most people but it could be built into a pretty decent axle.