It may be more practical to use the same fuel. ?
Unless you can find some way of taking diesel fuel from your truck's fuel tank, you'd still have to carry an extra fuel can with you, so I don't see the advantage of having a diesel generator just because your truck is diesel. And do they even make small, portable...quiet...diesel generators?
Maybe you can get a truck bed generator like Jungle Jim mentioned and have it plumbed into your truck's fuel tank...assuming they come in diesel models???
As far as solar, we have 400 watts of solar, 4 AGM batteries, an HPV-22B solar controller, and a 2000-watt inverter/charger (all from AM Solar in Springfield, OR). With this setup, we can run everything inside our rig with the exception of the A/C. We have the 2 Honda 2000's as a backup for those times when we have several cloudy days in a row, or are under trees (something we try not to do). We don't travel in weather extremes...for example, in the Southwest during the summer, or in the north during the winter...so we rarely have any use for the generators...we've used them once for running our A/C, and sometimes individually to provide power on cloudy days. And 99% of the time, we have clean, quiet power.
As far as being expensive, how much do you think it's going to cost to buy one of the large generators you're talking about, not to mention all the fuel to run it? Over a period of time, I'd be willing to bet that you'd spend less in total outlay for solar than for a large generator plus fuel.