So when does someone provide a diesel plug-in hybrid?

Toyota has in fact created a plug-in hybrid (but not diesel).

I have only heard of after-market conversions. Is there anything sold and supported by the automakers?

Hmmm those staid Europeans have only known and driven fuel sipping diesels for 50 years minimum. Really makes you wonder why Americans could not have caught on sooner than waiting for Honda regardless of California EPA rules. Sounds to me like the oil lobby is alive and oppressing gee thanks George... Hydrogen please and fill 'er up!

Diesel + hybrid = sale!

I thought VW would have offered a diesel hybrid by now, but no. And why not? Certainly the Germans can engineer something like a diesel hybrid.

One last WOW factor for me: Add to the diesel-hybrid a factory equiped vegetable oil tank/filter system in the trunk. It doesn't have to be too large, 5 gallons at most. The trunk is a great place to keep the veggie juice warm in the winter. There's only a couple thousand people already doing this to their current diesel powered vehicle. The only thing keeping others is the know-how. Can you imagine getting bulk veggie oil at the warehouse club? They would have to devote a tenth of their floor space for all the veggie oil they'd have to stock.

The reason that we are just now getting high mpg diesel cars like Europe has, is because we are just now getting ultra-low sulfur diesel fuel for those cars to run on. The new engines just can't take the old diesel fuel used in trucks.

FYI, maybe it depends where you live, but diesel doesn't _always_ cost less. It fluctuates independently of gasoline though. But this winter, diesel was a dollar more...

Europeans have 45% of passenger cars as diesel versions as 1) taxes on diesel are less so the cost per liter is less, and 2) per liter, a diesel takes you further. The drawback is a higher cost, a noisier and dirtier engine AND, due to the addition of turbo chargers to counteract the lack of torque, engine unreliability relative to a well-tuned gas engine. Take away the artificially lower cost, and there is no real advantage to a diesel. The Honda's hybrid failed because of its underperforming algorithims and drivetrain management relative to Toyota -- i.e. it was not competitive. Toyota is due to come out with a 2009 Prius that is bigger, faster and MORE economical.