In a interview with the downforce podcast Panoz said that they did build a new version of the Panoz GTR1. I guess its a street car for now. First I've heard of it. But just found this article too. Great stuff. Rather see that race than the stupid Delta Wing.
http://downforce-radio.co.uk/downforce-meets-don-panoz/
http://www.forbes.com/sites/samabuel.../#131c32d81925