How would you like to buy a car that has zero emissions, sprints from 0-60 mph in under five seconds, can do 300 mpg and is almost bulletproof in terms of its crash performance?

Thought so. And the bizarre truth is that you could buy a car with this wealth of amazing attributes right now, except that you would have to pay in the region of half a million euros to do so. That’s not because the manufacturers are having a laugh: high-tech means high prices.

The Audi R8 e-tron in the picture was well on course for production until someone did the sums and worked out what it would have to cost. After a few moments of mumbling and looking at shoes, the project was canned.

Almost every motorshow stand is packed with concept cars that display incredible advances in design, performance, economy and packaging, but what may come as a surprise is the fact that quite often these advances are genuine and tangible. The only barrier to them being in a showroom-ready machine is the price.

The home PC market is the perfect illustrator. Five years ago the idea of having twin-processors was almost laughable, given the costs involved. Currently, there are chips that far exceed the performance of even the best commercially-available machine, except that they cost a fortune to develop and so won’t reach the market for several years. Replace ‘chips’ with ‘engines’ and you can understand why progress in the auto-motive industry can seem some-what incremental.

If you want maximum efficiency, you need minimal weight, and that means exotic materials. Using clever high-tensile steel wherever possible shaves a few kilogrammes off, but to really crash-diet you need carbon-fibre. Trouble is it costs around 10 times as much as steel, which could add as much as 30 per cent to the list price of your car. There’s also one other small issue – you can’t hammer out a dent in a carbon-fibre panel or chassis, you need a new bit instead.

Then there’s the matter of propulsion. You have options here, given the huge budget. Go for the absolute latest battery and electric motor technology and you can have blistering acceleration (thanks to maximum torque at zero rpm). Add in a hydrogen fuel cell and you have the huge range to go with it. Except that there’s a price to pay here, too.

There’s isn’t much of a hydrogen infrastructure at the moment, so it would take deep pockets to get some delivered to your house. The cutting-edge of Lithium-ion batteries don’t come cheap especially when you need enough to push along 1,000 kg.

Another point that needs to be made is that keen manufacturers are to bring in these advanced machines time is a huge factor. Remember that a conventional car, with a normal engine, transmission, design and layout, takes around five years to get from a blank sheet of paper to the showroom floor, thanks to legislature, tooling, production, testing and so on.

Imagine how much longer a car with hydrogen and electric power, wireless controls and constructed entirely from unobtanium would take to make. As the old saying goes, the best things come to those who wait.