Luxury automaker Bentley is expected to debut its fastest, most powerful car to date at the upcoming Geneva Car Show. The “Extreme Bentley” is expected to take center stage at the show because Bentley claims the new plush powerhouse will tap its steam from biofuel. Details are scant, but the car clearly takes its design cues from the 600HP Continental GT Speed, the automaker’s flagship workhorse. Autoblog is expecting an “ethanol-drinking” version of a twin-turbo W12 to supply power behind the blacked out grill and beneath the hood’s new vents. [via autoblog]