Volks Wagon saying "no" was a due to their not wanting to have any of their vehicle associated with war. I don't think any other car companies are going to have that hang-up.
However, some companies DO have attitudes. The best example is the Alternators line.
Honda of Ameica wouldn't allow Windcharger to have a gun, because they thought it would give their cars a bad image. So Hasbro removed the barrel of his gun and now he has 2 shields (Overdrive, the Japanese Binaltech version, was allowed to keep the gun by Honda of Japan).
All the Decepticon Alternators are repaints/slight remolds of the Autobot Alternators because all the car companies want to make certain that their cars are good guys first and foremost, because they think making their car a villain will hurt the company's image and lose them money.
Stuff like that, I'm sure, is the problem the movie will have most with licensing vehicles. Volks Wagon flat-out refusing them is based on a sensetive issue left-over from World War II, and certainly won't extend to any other car company.