It can be done but the logistics of it turn most people off. You have to have a completely sealed off space around the generator, proper airflow to the gen, and then get all the wiring done with transfer switch and such. When you add all this up, carrying a portable generator seems easy.
Both Honda and Yamaha make big inverter generators. 6500 and 6300 watt respectively. They are about as quiet as you will find. I think they weigh around 200 pounds though. I don't know if you would consider that "portable".
2001 Ford F250 7.3l converted to F350 specs
2014 Flagstaff 8528RKWS
2 - 2006 model year Border Collies