at the sema show or whatever its called in detroit alot of companies (such as mercedes, toyota, jeep, and nissan) all have plans to offer diesel engines in midsized trucks and suv's. mercedes has also stated that they are seriously looking into bringing their diesel cars back to the US. volkswagon is already doing it like u said bd, and with other companies planning to expand their diesel market, i think we might finally be on the verge of a major growth in diesels.
mercedes also has an interesting idea on emmissions as well for a diesel, with no power loss (as they claim, but it sounds correct). there will be a second tank of some chemical that when mixed with the exhaust gasses becomes ammonia. in turn, the ammonia will convert the NOx gasses into nitrogen and water, reducing emmisions by 80%. (as claimed)
combine that with biodiesel, even fewer emmisions. then add an electric hybrid motor to that to improve gas mileage even more.