Building on the success of the 2010 Toyota Prius hybrid, which is close to sold out due to worldwide demand, Toyota is planning to add additional body styles to the Prius line.

Now, the first details of those cars have emerged, and one new model will apparently be a two-door coupe that targets the upcoming 2011 Honda CR-Z hybrid sports coupe.

An unsourced report in the British magazine Autocar says the new Prius coupe will use the same 1.8-liter four-cylinder engine and Hybrid Synergy Drive system as today's Prius hatchback.

But it will offer even better aerodynamics than the five-door, whose drag coefficient of 0.25 is close to the best among production cars today. It is also likely to be slightly lighter than the family Prius.

The Prius line will be further expanded with a small minivan, similar in size to the 2010 Mazda Mazda5 model. The Mazda van is one entire car class smaller than the 2010 Toyota Sienna that ranks among the top minivans sold in the U.S.

Both vehicles will face off against planned Honda hybrid models, perhaps in response to that company's recent efforts to make its entire lineup even greener and more fuel efficient than it had first planned.