Are there any diesel-hybrid (Both combined!) cars available in Europe with great gas mileage? Or in USA?

Answer 1

Not yet...

Mercedes Benz is developing one though. They are going to marry a diesel engine to the 2-mode hybrid transmission that was jointly developed by GM and then-DaimlerChrysler.

Toyota is similarly experimenting with pairing a diesel engine with their Hybrid Synergy Drive.

We probably won't see any diesel hybrids for another 2-3 years though, at the earliest.