After a quick read-over, it appears
this setup should fully power either standard or fast Alta chargers (it's 5kW at 50Hz, so figure 4kW+ at the reduced duty cycle; it may be available in 60Hz too, idk). Yes, it's probably expensive, may be difficult to install, inverter unit bulky, etc. - but extremely quiet / huge fuel tank / no lifting 240VAC capabilities might be worth it to many. I would've loved something like this during past camping trips and power outages.
EDIT: Just read through the
installation manual - it appears automatic engine speed control is an option (p. 9, #2), using a load-demand output on the inverter. If Whisper Power's speed control can maintain @ 1,700 engine rpm under varying loads (using 3:1 pulleys), it should work well and be fairly easy on both engine & alternator.
Ray