I did not know the Honda/Yahama inverter models (Which are well known as some of the least noisy generators) could be had in Diesel, Gasoline yes, and propane, but not Diesel... That said I can fully understand the lure of a diesel Genny... Fuel is safer to handle and unless the tank becomes infected (Alge) lasts rather well.
Onan and Genrac both make Diesel units.. But they are designed for mounting in an RV.. You could mount one in the pick up as well. .
Recommendation: IF you get an ONAN and your RV is 50 amp.. Get a 120/240 volt model. THEN on your sticks & bricks, have a proper generator transfer switch installed with an inlet.. Make up a cord that can go from the Genny to the inlet.. Comes in handy when the mains fail.
Home is where I park it!