Audi had an impressive diesel entry in 24/hr Le Mans ,,, and there is a very entertaining racing series for diesel tractor trailers in europe ,, the flat 12 powered MB tractors put out 1200hp... I think Peugot will have a diesel entry for LeMans next year.. I like diesel myself but I don't know when we'll see them here ... maybe as the donkey engine in a hybrid??
Emissions is the biggest hurdle. You can get diesels in the some states now, but they are either in a VW Rabbit or a 3/4 ton pile driving pickup.
I would like to be able to get a 1/2 ton pickup with a ~4 liter turbo charged 6 cylinder diesel. Put a variable power unit on the dash. Turn it to ~250HP for cruising up to 400-450HP for performance, all without shutting the engine off or leaving the cab. Of course fuel economy varies just as widely. You just can't do that with a gas engine.