Alternative histories are fun. Just ask Robert Harris. But we're not here to talk war-winning Nazis, we're here to consider the concept cars that nearly made it from the show floor to the dealership. Specifically the ones that really deserved to - not V16 supercars inspired by the Pacific coral reef and fuelled by ostrich eggs - but the proper stuff that would've made life a little sweeter if they'd entered the car market's bloodstream.
So, without further ado, here's our first that got away: the VW eco warrior powered by a Ducati engine. There's nothing that makes October 2014 seem considerably longer than six years ago than the Volkswagen XL Sport. More's the pity. Nowadays, when efficiency, performance and driving fun can apparently only be achieved by throwing more batteries at the problem, the notion of a small, carbon-fibre diesel hybrid with a Ducati v-twin transplant sounds like the finest of automotive fiction. Back then it seemed daft, sure, but also immensely desirable, incredibly interesting and no less viable for production than something like the original XL1, or a host of the other concepts that emerged at the time. All of them followed the fairly prosaic naming strategy of the XL Sport - CrossBlue, CrossBlue Coupe, Cross Coupe GTE, Sport Coupe Concept GTE - and all of made it to production with fairly minor tweaks along the way, because VW doesn't really do off-the-wall motor show vehicles. (Those concepts, just so you know, became the Atlas, Atlas Cross Sport and different eras of Arteon).
Alas, it wasn't to be for the littl'un. And with each passing year, that looks more and more of a shame. Because it ticked so many of the buzzword boxes that manufacturers love to see ticked for a new project: there was collaboration and synergy, by bringing together different brands from the empire; there was innovation and efficiency, with this being the fastest 200hp car ever made at 168mph; there was heritage, because Ducati v-twins are regarded like Ferrari V12s; and there was fascination (they particularly like that one) because of this car's incredible styling, spec and details.
To look at, the XL Sport was all supercar flair and drama - look at the doors! - only distilled into a pint-size package. Again, from a future-proofing and environmentally conscious viewpoint, what better than a downsized, less profligate - heck, two-cylinder - sports car that's still hitting 62mph in less than six seconds? While substantially longer and wider than an XL1,the Sport was still only 4,291mm long and 1,847mm wide. That increase in size was there for stability at speed, as VW pursued "the inclusion of uncompromising driving dynamics" into the XL's repertoire.
Furthermore, despite the size increase, the XL Sport weighed just 890kg; retaining the CFRP panels of the 1 helped the Sport's cause, as did the use of forged magnesium wheels and ceramic discs. There were double wishbones at each corner, VW suggesting that "the parallels with motor racing are impossible to overlook". Which it's easy to agree with, and also see much in the Sport of what enthusiasts should have been crowing for in a contemporary sports car: something light, intelligent, small, fun, fast and blessed with a brilliant engine.
Ah yes, that mighty v-twin. The XL Sport could have looked how it did and been powered by a lawnmower engine and it would have almost made this list. That it instead featured the howling v-twin from a Ducati 1199 Superleggera, a limited run celebration of the famed 1199, sits spot beyond doubt. Of course, the headline grabbing numbers were the 11,000rpm redline, the 200hp peak and the sort of bore/stroke ratio - 112mm/60.8mm - to make your head explode. Perhaps the most remarkable thing, though, was that it had all been made to work in a car, and with a seven-speed DSG, having only been "slightly modified" from the Ducati installation.
Who would have bet against the XL Sport being much more demanding to drive than an XL1? Given VW thoroughness in making the diesel-hybrid curio work, somehow ensuring that an 800cc, two-cylinder diesel didn't feel like it belonged on a farm and then melding it with a motor, a plain old bike engine must have looked like elementary work. Think as well of the increased proliferation of dual-clutch 'boxes in the motorcycle world now - it could have been made to happen.
All of which makes the XL Sport's status as a 'what might have been' all the more frustrating. It was so close. You'll be all too aware of why it was canned - the diesel saga coming to the fore less than a year later - and now look where we are. Volkswagen won't make another purely combustion engined race car, a lot of the exciting concepts have dried up and the sort of bullish, almost arrogant corporate determination that saw the XL1 make it into the world has vanished. Not long after the XL Sport debuted the world of cars began a pretty fundamental change, and the little VW represents perhaps the very peak of the creativity, vision and sense of fun that could be seen characterising the old era.
Don't misunderstand; it would have been heinously expensive - remember a diesel XL1 was £115k - some morons would have complained about torque and it had precious little to do with any other model in the range. But knowing that VW was serious about it makes the decision to can it all the more galling, if understandable given the circumstances - niche projects are always the first to be culled, if the hardest to let go of.
How serious were they? Look on the VW website, where it said 250 were going to be built. And then look at the press pack. There are 17 pages detailing the 205-section front and 265-section rear tyres, the 107 litres of boot space, the five-slatted louvre in the rear hatch that automatically opens to cool the engine, the digital display inside with lap timer and a piece of carbon atop that display to "completely eliminate reflections"; this was not simply a buck wheeled onto a show stand to draw the punters in. The XL Sport really appears like it could have been made, anodised aluminium accents, contrast red stitching, extendible spoiler motor borrowed from Lamborghini and all. Shame. One can only hope that, from this, Volkswagen and its subsidiaries are afforded the same freedom in future to show off their considerable aptitude again - perhaps the saddest part of the whole saga is how unlikely that possibility currently seems.