But it isn't just troubled artistes with a taste for mind-altering substances that have the monopoly on mad ideas - car makers have been at it for decades. For proof you need look no further than Germany - the undoubted home of motoring insanity. In just five months, it has bought us the BMW 7-series, the Porsche Cayenne and now this; the Smart Crossblade.

Although the standard Smart is hardly a shrinking violet, the Crossblade - 40 of which are earmarked for the UK - makes it look positively conservative. Effectively a road-legal version of the concept car that appeared at the 2001 Geneva motor show, it's based around the standard Smart cabrio and acts as a not-so-gentle reminder that the imminent arrival of a four-door model isn't about to turn MCC into a cosy, pipe 'n' slippers brand.

Best described as a cross between a Lotus 340R and a Mini Moke, the Crossblade has been shorn of its windscreen, windows and doors, while every other exterior panel has been either redesigned or removed in an effort to make it as close as possible to the original concept version. Underneath the new clothes lies the familiar TRIDION steel safety frame, albeit with a number of modifications to improve stiffness. The engine - an uprated version of the standard three-cylinder turbocharged unit - develops a perky 70bhp while the track has been widened front and rear to accommodate the unique 16-inch three- spoke alloys.

Inside, much of the traditional Smart furniture remains. The seats - waterproofed with a rubbery neoprene-like material - are decently supportive while the facia houses the stereo and controls for the basic heater. Unsurprisingly, creature comforts are few and far between. There's no rev-counter - engineers couldn't waterproof it effectively - while the floor is coated in tough-looking textured plastic.

In terms of driving, the Crossblade delivers an experience that sits some way between a Caterham and a theme-park roller coaster. With no wind protection to speak of, the hearty thrum of the three-pot engine is soon drowned- out by a force nine gale that buffets your head from every angle. Look down to where the door pockets should be and all you see is the road rushing by. Think of it as a four-wheeled scooter and you get some idea of what it's like.

Performance is decent enough. With just 70bhp on tap you won't worry many Caterham owners but because there's just 740kg to lug about, you can have plenty of fun wringing out every last drop of power from the seemingly unburstable three-pot motor. The same goes for the chassis which, again, isn't exactly track- day material. Despite wider rubber and track increases front and rear, the Crossblade is still prone to understeer in tight corners and is best experienced at brisk rather than high speeds. Smart claims a 0-60mph time of 17 seconds while the top speed is electronically limited to 85mph.

But what marks out the Crossblade from the likes of the old Mini Moke is that it feels unbelievably solid. It may look like an 85mph golf cart but it's built like an S-class. From the granite-like roll hoop to the scissor 'doors' that close with all the finality of Tower Bridge, the Crossblade is a seriously well-engineered package.

Like all Smarts, you either get the Crossblade or you don't. Start worrying about the price - a thumping ΂£16,000 - or the fact that it has no weather protection and you miss the point completely. Regard it as a piece of automotive sculpture that'll turn more heads than a Ferrari and you'll love it to pieces. Less, as they say, is more.