I agree with you on Diesel. I drove a 1.3l turbo diesel Lancia small SUV on the Autostrada for 5 days and it cost $65US to run all that time, it was a great drive too. But, Americans dont want Diesels at this point. I work at a BMW dealer and they have a diesel X5 and 335d and nobody wants them. Here in NYC, diesel is getting harder and harder to find and often costs more than a dollar/gal over gas.
BTW...I burn WVO in the merc.
A diesel hybrid would be fast off the line, quiet at a red light and may get as much as 60MPG. I'm sure Toyota is working on it while GM continues to delay the Volt