Upcoming car is now done (thanks to trnaslate in the section translation for ducth, czech, portuguese and polish).
To do one, add a car, select upcoming cars in the category and that's all. You hadn't to put pics or engines for them if you hadn't. When the car was in sale, a member have to add all the engines and correct the informations like the other cars before changing the category of the car (example here upcoming cars will be change in SUV). And it will be automatically translate in the corect section (road car or race car)

Interesting, this wasn't how I had it in mind, but I think it works rather well.

Desscythe17 wrote
that was the most easy to do for me and quickly.

If the car makers can't stop making these stupid SUV's can they at least stop making those stupid commercials about cars Off-Road capabilities?
I mean Classic Mini can go on that 'off-road' without any problem...