The word is that Mazda will use similar hybrid drivetrain like Toyota, just with their own skyactiv gasoline engines: Mazda 3 Hybrid: first images and details released | CarAdvice Mazda and Toyota agree to hybrid technology license | CarAdvice All-New Mazda3 Unveiled; Includes Hybrid - HybridCars.com Any more rumors?
I must say "Japan only" lowers my enthusiasm. Even as it is, I hear of many models by many manufacturers that will only be sold in one country or state. It cannot be popular if you can't buy it.
Here is my current thinking -- I'll try to say it more clearly this time: USA is not interested in hybrids because they mostly are made in Japan. Also we have low gaso taxes. The hybrid "pay-out" math is getting questionable - unless you put on many miles/yr. Prius works because it is highly practical family/hauling car with no ICE version to compete with it. We in USA are pushing/subsidizing Plug_ins. In my state (VA) I would seek out the non-hybrid ICE model of any car in the future, or maybe used hybrid or used Plug-In. Mazda 3 looks good on paper - sort of the Prius ICE that I need.
