I finally broke down at bought LEGO 42136, and while it's not great, it's inexpensive and mostly green. I have never built an alternative model, so I figured this would be a good little set for me to try it out. This is the result.
The articulated dumper features steering and dumping. Most of the parts from 42136 are used, with a couple left over (including spares).
Dumping is manual.
Steering is controlled by the HOG on the roof.
Instructions are available at rebrickable.com if you are interested.
I might have to try another B-Build, as it is an interesting challenge.