[dsraven]

stretching the fenders and hood, front to rear, to fit a long engine will be a challenge and will make interior room quite small I think. you could tretch the can with a bigger door opening I suppose. again, a challenge though.
I have seen a few diesel swaps online as well and to me they usually have too much tire and also look too short since the ones I seen also use the truck bed and not a flat deck.
do the math on the track width front and rear and compare to to the task force you have. possibly a single rear wheel donor truck and them swap in a dually axle would be better. the track width up front would be more inline with what you need.the track width out back would be covered by the deck so not as noticeable and wouldn't look like a cobbled together thing.