As mentioned in a recent A-C-E post (linking to a 26MAR07 Defense Review post), Gibbs Technologies (Warwickshire, UK) and Lockheed Martin have agreed to develop a family of high-speed amphibious vehicles designed specifically for military operations, based on technology Gibbs uses in vehicles for civilian use.
Here's a better image:
And here's a video.
Remember the James Bond car which converted to a submarine by retracting its wheels very similarly? (Scroll down at this link to see it with the wheels retracted.)
Gibbs and Lockheed Martin will advance the development by integrating expeditionary command and control capability, armor, and weapons systems.