As you may already know, the Automotive X PRIZE has a blog. They recently posted about the high cost of high MPG.
Meanwhile, the X PRIZE Foundation news ticker points to an article in BusinessWeek about a low emission, high-performance 3 wheel vehicle by FuelVapor. The car gets 92 mpg and takes 1.7 G's during cornering moves. The article states that "The alé will be an entry in the Automotive X-Prize, a competition aimed at fostering the design of viable, clean and super-efficient cars that people still want to own.".