[css-sizing] Extrinsic sizing of controls

I would like to discuss standardizing the extrinsic width of a text area when a width is applied. We could apply this more generally to other controls but I thought I would start where I have a decent test case.

Take the following testcase: http://jsfiddle.net/es24Q/

I prefer Firefox's implementation of this, as it sets the width to what the author declared no matter how wide their own scroll bars are.

Thoughts?

Greg