Sure, if it's a fixed width, it's super easy using CSS, and not at all offensive or laborious. It's when you need it to scale in both directions that things get choppy. Some of the solutions have a staggering amount of divs stacked on top of each other to make it happen.
My solution is to dictate to the designer that if they want to use rounded corners (for the time being), it needs to be a fixed width. Designers love rounded corners (so do I), so I find this to be a reasonable compromise.
