I was sitting there waiting for the car to warm up and clear up the windows some...and was wondering if there was a rear defroster that can be installed?

Dave

 

I had an OEM one on a '72 Cutlass Supreme years ago. It was just a blower that was mounted in the rear package tray. I seem to recall it having a high and low setting only, and it did a mediocre job at clearing the glass. Having a glass shop install a more modern version would probably work much better.