It's long been the dream of Toyota's U.S. arm that the company would add additional body styles to the Prius line. And Toyota finally gave the nod to that idea earlier this year.

Now, details are starting to emerge on the new models that will join the all-new, third-generation 2010 Toyota Prius, currently sold only as a five-door hatchback.

One of the new body styles will apparently be a two-door coupe, specifically meant to target the upcoming 2011 Honda CR-Z hybrid sports coupe.

The British magazine Autocar reports that the new Prius coupe is to use the same 1.8-liter four-cylinder engine as the current Prius hatchback, but will be lighter and more aerodynamic.

Given that the hatchback 2010 Prius has a drag coefficient of 0.25, a new Prius coupe might best the single most aerodynamic production car in the world, the 2010 Mercedes-Benz E-Class coupe (at 0.24).

And that might give it fuel economy even better than the Prius hatchback's current 50-mpg rating.

2009 Honda Skydeck Concept

2009 Honda Skydeck Concept

Also coming is a Prius minivan, which is expected to compete with a production version of the Honda Skydeck hybrid minivan concept shown at the recent Tokyo Motor Show.

Whether this will be sold in the States is less clear, since Toyota hasn't offered the smaller minivans it sells elsewhere--about the size of a 2010 Mazda Mazda5 model--in the U.S. thus far.

2011 Ford C-MAX

2011 Ford C-MAX

Its 2010 Toyota Sienna minivan consistently ranks among the top minivans sold in the U.S. But more small minivans are on the way, including the upcoming 2012 Ford C-Max.

And if Honda launches a hybrid minivan in the U.S., Toyota is sure to want to protect its hybrid dominance by doing the same.

Both new Prius models, in fact, will compete with an expanded range of hybrids from Honda, which recently redoubled efforts to make its entire lineup even greener and more fuel efficient.

For this year, however, the sole Prius model soldiers on, selling like hotcakes. In fact, as we've noted before, the 2010 Toyota Prius hybrid is close to sold out due to worldwide demand.

[Autocar via GreenCarReports]