Scion has the hip, urban image among Toyota's marques, and I believe this would compliment the curent line up. If there's one thing that Scion has accomplished, it (along with Mini) has made a small car be seen as more than just basic transportation. There's been the Subaru Justy, the Ford Festiva, Geo Metro, Dodge Colt, Toyota Tercel, up to Chevrolet's current Aveo, and they have all been produced and marketed as basic, low-cost transportation. Scion has changed that, making entry-level cars into objects of desire, not something you bought because it was the cheapest thing on the lot.
The current cost of fuel just makes it even more compelling to bring this car over. There's not a lot of fuel misers for sale, most having died out as the SUV craze took hold. It's time to bring them back.