Hybrid Gas Water Heater

The wife's been complaining about the limited hot water from our ancient (ca 1996) tank-type water heater.  In Japan, of course, they use tankless heaters, which is evinced by the major manufacturers being Japanese: Rinnai and Noritz.  Anyway, recently when talking with a builder-type dude, he mentioned hybrids as being the favored type now.  When I looked into it, most hybrids are electric, except for the Eternal GU120.  The size of the tank isn't clearly specified, but from one of the documents it's implied that it's 2 gallons.  $1400, with a $300 tax credit for 2013.