We’ve been waiting for what seems like an age to see the first road-going prototypes of Aston Martin’s next big thing, the Rapide four-door GT. Now, spy photographs of the car have surfaced on an American blogging ‘site, showing that road-based development work on the car is finally in full swing.These photos show a British-registered Rapide stopped for refuelling at a motorway service station somewhere in continental Europe. It’s clearly a very early prototype; the car’s rear doors are held in place by clips. However, the images do show that the car’s basic exterior design and proportions haven’t changed much since the Rapide concept was shown two years ago.Many within the motor industry were expecting the Rapide to enter production this year. By the look of these shots, and according to the latest inside information from Gaydon, the car will be more likely to arrive sometime in 2009. Aston is expected to announce that the car will be developed and assembled outside of the UK, by an engineering specialist like Karmann, Magna Steyr or Pininfarina. As Aston CEO Ulrich Bez recently told Autocar, there isn't enough spare capacity at the firm's Gaydon assembly plant to build the Rapide there, and the project wouldn't be profitable enough to merit an investment in the facility to enlarge it.