To understand the importance of the mix, says Max Warburton of Bernstein Research, compare the cost of producing a small car such as the popular Fiat 500 with that of making a hulking sport-utility vehicle such as the Audi Q7.

ECONOMIST: The car industry

Mr Schreiber's suggestion that Volkswagen Group's plant in Bratislava might get the new Bentley is based on its proven ability to produce SUV models for other marques within the group, such as the Audi's Q7 and the Volkswagen Touareg.

BBC: Bentley considers assembling new model outside the UK

Climb aboard the Q7 and you quickly understand why Audi (audiusa.com) is considered the premier fabricator of automotive interiors.

CNN: The new Q7: One outsized Audi

Audi's great diesel vehicles--the A3 TDI and Q7 TDI--didn't make the cut for our list (the luxury brand name carries a hefty price premium, though Mercedes-Benz was able to break through that ceiling).

FORBES: Magazine Article