chassis r the same jus different mounting places for cab & tub etc
i do have to burst ur bubble guys but the dual cabs have a shorter tray then spacecabs
the rear wheels jus behind the cab if u notice in pics
in the above rendering it would b called a stretched dually
anothe guy on bscene from aus is stretching a spacecab with a singlecab tub
his build ups in under construction section here aswell
iv even seen singlecabs with dually tubs which look like sum kids toy haha
it aint a mazda but i thought id throw up a supershorty pic