The M-1 Flatrack:
This is considered by the military to be the ideal flatrack. However the increased weight of this bulkhead flatrack AND the increased cost of the design has forced it to be designated as "limited standard".
They certainly seem fairly basic and buildable out of brass tube and Evergreen shapes.
Gino - just to add further to your statement above.
There is already an Army contract in place with Oshkosh to upgrade ALL the existing HEMTT A2's to the new A4 design. These upgraded vehicles will, upon re-delivery carry an "as new", full vehicle warranty and be given new body/frame ID numbers.
The HEMTT and PLS families of vehicles are here to stay!
Yet the Mk probably costs less...