In the GMT 400 platform they did build a "light duty" 3500.
It was 9,200 GVW.
They were govt. rigs, most went to the Forest Service.
The ones I've seen had FF 14 bolt rears, the 3500 A-arms/front end, and a 5 speed manual trans.
Also, no power windows/seats, no carpeting, just rubber floor mats...