MacChef,
Welcome
The term "whale tail" is a name for the tail on the 80's Porsche 930. If you have a 993 TT, you already have a tail, of course. If you're looking for something larger, check some of the companies that make glass and carbon tails:
http://www.mashaw.com
http://theracersgroup.com
http://www.gt-racing.com
You should get some good pics there. Good luck!