Yes I have run the house off of our Prius. Just clipped a 12VDC to 230VAC inverter to the 12V battery and connected the output to the house via the generator/grid change over switch.

The Prius is turned on as 'ready' and sits in the driveway locked.

As the house consumes power the 12V battery is recharged via the car's DC:DC inverter from the 5kWh traction battery. When the traction battery is low the engine starts and runs for 10-15 minutes and charges it up then shuts down for an hour or so. The output is limited by a 100A fuse in the DC:DC inverter so a 12VDC inverter limit of 1,000W is recommended. Fuel consumption was less than half a litre an hour, about a pint. It will of course vary with the demand on the 12VDC inverter. A full tank will run for days and overall the whole rig is very quiet.

One kilowatt obviously won't do everything but is enough for lighting, refrigeration and entertainment.

My inverter is a 'modified square wave' which is not that good, so I had to disconnect the mains powered smoke and CO alarms as their instructions say they are sensitive to supply waveform.

I forgot to add.
We have 6kWp of solar but it is grid tied. When in grid out I try to connect it directly to the house, the Prius rig or to the Honda generator, the system voltage hunts up and down violently and quickly shuts down the solar inverter. It really needs the buffer of a live grid to work properly.