No supercars will ever use diesels?????????? <A BORDER="0" HREF="http://www.supercars.net/PitLane?displayFAQ=y"><IMG BORDER="0" SRC="pitlane/emoticons/sad.gif"></A>(((((((
I actually dont think any true supercar company will. But you might see them from allround manufacturers, like the R8 of course.
I don't think that would sit well with Lambo fans to be honest. I can see only companies like Peugeot doing a special supercar, especially with their Le Mans project.
It's obviously Porsche. The Germans love diesel technology, and Porsche has access to all the latest projects through their connection with VW.