Theme switching determined by screen size?

Hello,

I was wondering if there is a way to automatically switch a theme with either PHP or javascript depending on a users screen size. I am embracing Responsive Web Design through media queries, but I feel a better way to go about this would be if I had the power to switch themes. That way instead of hiding certain pieces of content (sidebar, jQuery carousel, etc.. ) with CSS I could build a streamlined theme. I know there are plugins that do it based on device detection but thats not what I want.

Any ideas?

Thanks!