I agree that cars are getting more interesting but the cost for setting up the tooling will get hit by the bean counters and therefore not every sketch line will get implemented. (Remember the world recession).
I would strip the sketch back to the major concept lines and then render that, removing the minor later sketched lines.... (If I had the skills that you have)
Ps that last one you have done can you re-render in that mad purple colour you used earlier....... IMHO that would look awesome in that colour... That purple really grabs the attention..
Ford have lime green and asbo orange.....
Vauxhall have a chavy blue.
SEAT have lime green and Yellow, however that purple would really set it apart from all other manufacturers