The folks in the UK have already had the Gibbs Aquada boat-car for a while, but us Bond-aspirers in the US will have our chance in the first half of 2009. The best news is we won't have to have Her Majesty's finance department for this one, since it'll be under $100,00 and be road and water legal.
The bad news is that you'll probably have to have a boat license to drive it. But nobody ever said going 100 mph on the road and 30 mph in the water came easy. Unless, of course, your name is Richard Branson. You'd get a personal escort from the Coast Guard.
Gibbs Aquada: The First Boatmobile You Can (Almost) Afford [Popular Mechanics]