After last year's $3.24 million sale of Harley Earl's 1954 Oldsmobile F88 concept car, collectible American concepts have come out of the woodwork for this year's event, including the 1954 Pontiac Bonneville Special pictured above.
In a more contemporary vein, the very first 2007 Ford Shelby GT500 Coupe will cross the block at this year's auction.
The auction has extensive live and tape-delay coverage in North America on SPEED Channel, starting tonight at 7p.m. ET.
Pictures of the rest of this year's American concept cars after the jump.
1953 Ford Vega Roadster - the "Gardner Special"
1950 GM "Futurliner" Parade of Progress bus
1964 Pontiac Prototype Banshee XP-833 Coupe
1953 Chrysler d'Elegance Sports Coupe