Granted, no one has produced anything like this with the LLT, but it is simply mistaken to believe that V6's aren't capable of producing 1000+ HP. Here are a few examples.
http://www.myshqipvideo.com/0_video_...20Engines.html
http://www.carsession.com/car-news/1...n-r35-gtr.html
http://www.mx6.com/forums/australia-...ze-gemini.html
The big difference is it is EASIER to make big power with a larger displacement engine. Some like to go the easy route and others like to take a more unique route. With time and money you can do a lot with the LLT engine, but be prepared to break things (just like the first guys to mod the LS3 engines).