Maybe 'chubby' is the wrong word. She is not so slim like typical porn stars. But I like girls with very big tits, a round ass and feminine curves. Karla James, in my opinion, has a body at the limit. On this pic
http://www.bigboobsalert.com/pics3/grand_bahama10.jpg
you can see that she's got a lot to offer. But damn, she is hot anyway!
The problem is that not all body shapes are equal.
Some women, of the same height, can weigh less than Karla and be in far worse shape. It's all about the width, the slenderness of the stomach, and where the weight goes into her breasts and hips.
I love extreme hourglass women, and the great majority of them are softer shapes. Some women have really unreal, tiny mid-sections, but their overhanging breasts and womanly hips, ass and thick thighs suggest to some they are overweight -- yet they have are still 12"+ more on their hips and bust than their mid-section.
Chloe Vevrier and Karina Hart are two extreme examples of this at 40-28-40" -- very slender, just wide, fucking hot curves on a shorter frame, not fat at all. Look at them from the side and you can easily see how slender they are.