2008 Lexus LS600h L - Why does this car exist?

MIAMI - If, like me, you are on the look out for a new, fuel efficient car, it was hard not to notice last week's launch of the latest hybrid from Lexus. In terms of clean energy engineering, the LS 600h L is perhaps the most interesting auto on the market today. It has been called the first "super ultra low" emissions muscle car. Weighing in at nearly 5, 000 pounds it combines a purring V-8 engine and smooth electric motors with emissions scrubbing technology. But its gas mileage is anemic. More on that in a bit.