The very nature of a concept car is to express something that production cars can't. Be it design language, cutting edge features or out-of-this-world technology, more often than not these cars could never be put into production. Sometimes though, concepts are tantalizingly close to being realistic prospects. That makes it even more tragic when they never make it past the prototype stage.
There's a myriad of reasons why these concepts never become anything more than that; often they were simply never meant for production. Cost issues and return-on-investment calculations are also a common reason, as manufacturing executives don't like to spend more than they'll earn back on developing a model. Whatever the reason, these ten concepts could have been so revolutionary if they'd been put into production that it's a real tragedy that they never were.
10 Chrysler ME 4 Twelve
Chrysler is hardly an inspiring brand today, with it's lineup of minivans and aging 300 more likely to elicit yawns than gasps. Back in 2004 the brand had big plans though, as they designed and built a V12 supercar.
The Mercedes-sourced engine was good for 850hp, with the car's lightweight construction meaning it could pull 0-60 in 2.9 seconds. That's still seriously fast today, but back in 2004 it was crazy. Chrysler at one point intended to produce a limited run of these cars, but cash flow issues and the impending financial crash meant that only two prototypes were ever built.
9 Maserati Birdcage 75th
As its name suggests, the Maserati Birdcage 75th was built to commemorate a 75th anniversary, not of Maserati but of the concept's designers, Pininfarina. The car was designed as a one-off special, but was fully functional and featured a Ferrari V12.
The most striking feature of the Birdcage 75th was its lack of doors. Instead, to climb in and out the driver had to lift the whole front end of the car's bodywork up. It was built on the chassis of a Maserati MC12, and shared many of its components. As it was essentially a design showcase, the brand only ever built one example of the Birdcage 75th.
8 Peugeot Onyx
Peugeot are a brand known across Europe and Africa mostly for their wallet-friendly but quirky cars. This concept was a huge stylistic departure for the brand, representing Peugeot's goal of proving its capabilities as a cutting-edge manufacturer.
The copper sheet metal on the car was designed so that over time, it would oxidize and turn green. It's a completely unique take on the idea of cars rusting, taking what's usually seen as a negative thing and turning it into art. As the Onyx was built as a showcase, Peugeot only ever made one and it's not known where that example is today.
7 Nissan IDx
Nissan rose to fame across the globe for its no-nonsense economy cars like the Datsun 510 and 240Z sports car. In recent years, it's lost its way a little, selling aging models that, apart from the GTR, are all pretty boring. When the brand debuted the IDx in 2013, it was a breath of fresh air and seemed like it could herald a new era for the Japanese marque.
The IDx was designed as a modern take on the 510, aiming to recreate the golden formula of solid build quality, affordability and attractive design. Nissan was at one point very serious about putting the car into production, with several executives dropping hints that it was near ready. However, Nissan's poor sales have meant the brand has had to make serious funding cuts, and it seems the IDx was among the projects that was canned.
6 Cadillac Ciel
Cadillac is another brand with an image problem at the moment. Every few years it seems a new executive is brought on at the company, each with a different idea of the direction the brand should go in. As a result, it seems the company's most exciting projects have been cancelled before they've ever reached production.
One of the most tragic examples is the Ciel Concept, debuted back in 2011. It was praised for its swooping design harking back to the Caddy land yachts of old. In 2012-13, several reports surfaced that Cadillac was planning to make a production vehicle based on the Ciel. Unfortunately, GM decided that investing in the Ciel wouldn't bring big enough returns, so it never made it past the prototype stage.
5 Spyker D12 Peking-to-Paris
Dutch automaker Spyker have had a strange and varied history that involve everything from partnering with Louis Vuitton to buying Saab then going bankrupt. One of the many ventures that didn't quite work out right for Spyker was the D12 Peking-to-Paris, an ambitious concept that was in many ways ahead of its time.
An ultra-luxurious super-SUV would be fairly easy to make a business case for today, as millionaires can't seem to buy enough of them. Back in 2006 when the concept first debuted at the Geneva Motor Show, the idea of a big posh 4x4 with a 500hp V12 seemed absurd to many. As a result, the brand never found the money to put the car into production. Spyker recently went bankrupt yet again, so it seems it's unlikely the Peking-to-Paris will ever roll off a production line.
4 Shayton Equilibrium
The 2012 Equilibrium by startup manufacturer Shayton spouted bold claims when it was revealed. A 1,084hp V12 engine was supposedly going to enable the car to pull a 2.9 second 0-60 and reach a top speed of 250 mph. As with many startups, Shayton's press releases promised a lot more than their team could deliver. As far as it's known, the brand never even made a fully-functional prototype.
It's a shame the car never happened, as the designers did a great job in making a timeless design. It still looks modern even ten years after it was unveiled. With today's technology, a thousand-horse hypercar is very much a realistic prospect even among the more cash-strapped of boutique manufacturers. Ten years ago though it was too much of an ask and Shayton never delivered a single car. Strangely, their website is still live and promises the car is "coming soon".
3 Vision Mercedes-Maybach 6
Mercedes' first attempt at reviving Maybach wasn't successful, with the 57 and 62 models selling generally poorly. It was partly because these older models were based on an S-Class and looked too similar to their cheaper counterparts. For Merc's second attempt, their designers went in exactly the opposite direction.
The elegant curves of the 6 are a unique combination of styles, taking inspiration from Maybachs of old. Sadly, Mercedes have not announced any plans to make the 6 available to customers, apart from lending it to Drake for his "Laugh Now Cry Later" video. Instead, they opted to produce the underwhelming Maybach GLS SUV, which by most accounts is a disappointing car.
2 VW W12 Nardo
The brand best known for the introduction of the "people's car" did briefly flirt with the idea of producing this W12-engined supercar in limited numbers. Three different W12 concepts were made between 1997 and 2001, with the last one being the W12 Nardo.
There was a lot of hype around the car, including it getting featured in video games such as the Gran Turismo and Test Drive series. Ultimately the brand decided against producing any consumer examples, but the car's engine lived on in the Audi A8 and Bentley Continental GT.
1 BMW 3.0 CSL Hommage
When it debuted in 2015, the 3.0 CSL Hommage garnered the best reception a new BMW had in decades. It was universally lauded as a perfect modern-day interpretation of the classic 3.0 CSL, with the right balance between retro-influences and contemporary design. So, did BMW take this incredible reception and turn it into an amazing production car? Of course not.
Executives decided that retro-modern cars were not the direction that the brand would take, and so the 3.0 CSL Hommage was never developed any further. In recent interviews, the company has had to defend this stance, even saying that developing a new 3.0 CSL was a "tempting" prospect. BMW's design boss has only said that he thinks it's, "not exactly necessary at this point in time", so fingers crossed for a retro-modern production Beemer in the future.