It kind of makes sense. Jeep is all about driving off-road. Rallies are partly about driving off-road, albeit on gravel tracks, and doing it fast. So here's the Jeep Compass, the off-roader/rally-car fusion, where Rubicon Trail meets East African Safari.

Do you buy that as an idea? Chrysler, owner of the Jeep brand, is hoping very much that Generation Y, as sociologists and marketing people are apparently calling the 14-to-24-year-olds who represent the next big wave of affluent, brand-savvy consumers, will do so. Especially as Jeep is the third most-recognised aspirational brand among this group, in the US anyway.

The Compass was unveiled at January's Detroit Auto Show, along with the Willys2 extreme off-roader powered by a Mini Cooper S engine, the Dodge M80 compact pickup and the Dodge Razor that we've also sampled (page 47). All except the Willys2 (which is made of carbonfibre on an aluminium frame yet still weighs 1350kg) have steel body panels, which shows a degree of production intent. And all were built by Metalcraft in California, which has made Chrysler's show cars for many years.

Now it's out in the open, at Key Biscayne south of Miami to be precise, with sand in the tyre treads. And the Generation Y types wandering up from the beach seem pretty impressed. The Compass is a faintly disturbing topological distortion of familiar Jeep forms: seven vertical grille-slats are flanked by raised round headlights, but the front is raked back and flanked by typically Jeep trapezoidal wheelarches which have spread right up to the bonnet sides. Framing huge 20in wheels, these arches have what Chrysler designer Chris Schuttera calls a 'digital' design, in that their angles and edges call to mind the chiselled graphics of, say, Lara Croft and her adversaries.

From the side the Compass is wedgy, with a fast windscreen line, and towards the rear corners it goes all hatchback on us. Does that rear side window look like a Corolla three-door's to you? Or that rear light like an Audi's, if you disregard the inset circles? But if you look across the roof, you're back to scuff-proof toughness. The surface treatment is a Xeroxed-up version of the high-grip aluminium floor you'd find in a Pret a Manger sandwich shop.

Inside, all is metal and aeronautical. This is the work of ex-Royal College of Art student Jordan Meadows, with dials like oversize stopwatches even down to the push-buttons, and knurled-edge eyeball air-vents like something out of a Boeing 707. The column stalks are tubular aluminium, but the best bit is the autobox selector. This has a toothed quadrant into whose five notches fits a spring-loaded transverse pin, disengaged with a detent button and moved with a lever. Never has a selector been more obviously mechanical. Whether nannying product liability legislation would deem it safe for unmonitored fingers is another matter.

The four separate seats are trimmed in green leather and Gore-tex, and the rear pair fold down. On the rooflining, either side of a full-length overhead console which mirrors the central floor-level backbone, is an abstract map with a grid and contour lines. And, naturally, there's a compass in the dashboard.

This is all very fine, but to fulfil the crossover role the Compass needs to be a sharp, agile, involving drive as well as a rock-hopper. But it's built on the monocoque underpinnings of the latest Cherokee, which might not sound very promising. Still, a well-located live rear axle never did the MkII Escort any harm, and the double-wishbone front suspension is both unbreakable and of decent geometry.

Power comes from the Cherokee's 3.7-litre, sohc-per-bank V6, which delivers a lazy but torquey 210bhp and sends it to all four wheels via the automatic transmission's four speeds. There's enough urge to jolly the Jeep to 60mph in nine seconds, and the Compass does sound blaringly enthusiastic with its free-breathing concept-car exhaust system.

Come to a corner, and the Compass will turn with more eagerness and less lean than a taller Cherokee, whilst the steering is crisp enough and the suspension firm enough to give a passable hint of sporting intent. It's certainly no Impreza WRX, but it does feel most of the way towards a credibly-honed production car.

It could catch on. After all, no-one has done a truly sporty off-roader before.