I used to be a proponent of electric jacks, but now I'd seriously consider going manual if ours ever dies.
Even if the tongue is really heavy, you aren't lifting the entire weight and you have a mechanical advantage. The times I've had to crank ours (a '95 30', with a third battery and a large inverter under the front couch), I've had no problem at all. It's quiet, reliable, and doesn't rely on the battery. Try your manual crank on your trailer and see how hard it is.
The one thing is that you'd have a top of the line trailer with a manual crank jack...it might just look odd. But if that's the worst problem...
1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel
Sold but not forgotten: 1991 Airstream B190
Sold: 2006 F-250 6.0L Powerstroke Supercab