Like to see that myself
I'll bring an Amp Clamp home and measure output at idle with nothing on and then slowly bring everything on; headlights, high beams, road lamps, heater blower, stereo at low volume and cranked up... I'll note the amps, voltage and RPM as well.
I guess I could take it to a buddy and have a load test put on it... I know they can load test a battery. I'm guessing they can load test an alternator too.