They did manufacture a prototype, though. Not sure if Seb. drove it or not, but I seem to recall he did. There is a video on (GT5 TV, is that what it's called?). And you must not know Dieter very well (i.e., at all) if you have to question whether he likes to spend money or not!Just check out all the cool stuff in the museum in photo-mode.
http://www.youtube.com/watch?v=u6tGoMBxldU
Technically the video is of the x2010
There was no drivable X2010. They made a model. That was all.