If you handy guys want a project then why not install a 4 cyl Isuzu or Mitsubishi truck diesel into a pick-up.The engines are near bulletproof,have dealer support,& get suprising mileage out of 4-5 liters.Pretty smooth too.The 2001 GMC W-4500 that I occasionally drive uses a 4HE1 turbo diesel &,w/a 14ft box will get low-mid teens @ 65 on the highway.Picture an eight foot wide ten foot tall 12,000lb brick through the air.
IIRC,there is a kit to put the older(180-220hp-400lb ft) 4BD1-T(Isuzu) in front of a 4l80e trans in a GM truck.
I'm not handy enough, unfortuantly.
Yeah, a Ferrari diesel!
small displacement with lots of cylinders has it's own problems with efficiency, complexity, weight, and cost.
Well, from what I've seen, for efficiency you generally want as few cylinders as you can get away with. Lacking Ubermaterial for the shafts and such, single cylinders are limited to pretty small jobs where you can overstrength the shafts to a large degree rather trivially. Or at least have a relatively huge mass in rotation to keep stuff even. As you get larger though, relative strengths get smaller, it takes more material to do things, and you end up just accepting the complexity and efficiency penalties to put more cylinders in.
A high torque(not necessarily 200hp) 4 cylinder engine with a 5 or 6 speed transmission should be able to propel a light truck through most anything somebody who isn't looking to pull heavy trailors will want it to do. While getting good fuel mileage. Might even beat many of the hybrids, at least on the highway.