Japanese Domestic Market Toyota Sera was a nice little number. Made up to '98 with a 1.5l engine. Weighs 900kg (1984 lbs). Being JDM you probably will not have their Cd numbers. Japanese cars may have big Cd numbers but their frontal area is small. They only make it bigger for the American market and then try to sell to the affluent market worldwide.
Serialk11r is right most of their cars are found in countries where people spend more time in congested cities. In which case; keeping weight down is more important than aeros. Kei cars are smaller with 3 cylinder engines and used in cities where they are not taxed for taking up so much space and high emissions.
Germans have their Autobahn and the big sedans are only used by upper-middle class people, privately owned businesses, taxis or company leased. Germans being practical, do not use big cars. Not when half of their income goes to taxes. In general hatchbacks are more popular in Europe with the masses.
If you are in America or even Australia, its basically because all these manufacturers have you in their sights for the Merc S400 hybrid. Everybody else who falls for it is a bonus.