2008 Ford Taurus
The new 2011 Ford Taurus is nicer looking on the outside than the previous generation Taurus. But the old Taurus was known for a cavernous interior and high arched roofline that created almost excessive headroom.
2012 Volkswagen Beetle
2011 Hyundai Azera
2011 Kia Rondo
2011 Honda Fit
The Fit is a prinme example how a small car can be "fitting" to a larger driver. The high roof-line of the car gives more headroom than one will find in many mall cars, and the interior is under-stated, giving the whole cabin of the car an airy, roomy feel, as well as being actually comfortable.
2011 Honda Element
Better get one of these while they are still on sale. Honda is discontinuing the Element. As you can see, there is hardly a friendlier package for the larger driver. Both side doors open for massive access getting in and out. The driver position is uncluttered and considered one of the roomiest vehicles on the market. It's also rated about the most dog friendly vehicle as well.