I remember they were "THE" thing 10 years ago, fairly low torque limits were their downfall.
"diesel over electric trucks".. Gas over electric is the chevy volt, I always thought a light diesel along the lines of the VW diesel (pre scandal) would net even better MPG's.
Maybe a RWD large diesel engine, electric generator/starter, CVT, automatic clutch, electric motor, driveshaft, axle.. Add a reasonable battery pack for regenerative braking and to help launches.
Stop and go on electric / battery. Launch on electric, with the diesel backing it up (and CVT kicking in once moving). Cruse with the electric disengaged using the CVT to power the axle direct from motor. You won't need a massive CVT, just 200-300 lb feet through it, the electrics can handle the rest.