Have to agree with BLK on this point. The last car GM did right (besides the Vette) was the new Monte Carlo. There is a blue SS running around Wiesbaden with the Jeff Gordon race livery and yellow-lettered Goodyears. Not exactly Retro, but still a sweet looking ride.
Edit: Couldnt get the pics to load, so giving links to one on Flickr instead.
http://www.flickr.com/photos/buglugs/2085585483/
http://www.flickr.com/photos/buglugs/2085585361/