While not a duster, a bodies are represented by a 68 Dart in current Historical trans am style races
https://m.facebook.com/media/set/?set=a.649117328446416.1073742768.522888894402594&type=3
I am not sure if this is the only a body running in these races but I did get to see it race at the long beach grand prix a few years ago when that race series had a stop here.
I think the biggest drawback (just my opinion and 100% speculation) is that the more narrow body of the A body style vs E body was the biggest factor as to why it wasn't as popular for races where hard cornering was involved. I imagine that with the wider body style of the E body, (again I am only speculating), that teams could have a better "leverage point" against the center of gravity for the lack of a better term. And also not have as much front/rear overhang past the wheels. Again I am not by any means an expert but I always wondered the same thing as to that there had to be a reason why Mopar didn't invest in an "trans am" A body since it was a lighter platform.