Lightbox for post bodies

Here’s an awesome idea. How about coding a plugin or theme modification that would “lightbox” the post body when you hover the mouse over the post body?

Here’s what I have in mind. If you move your mouse over the body of a post, all sidebars and headers fade gracefully away – to black or some other color – leaving only the POST itself, in its simple glory. Then if you move your mouse outside the post body, the rest of the sidebars and other content fades back in again.

Does anything like this already exist? Could it be coded as a plugin, or would it have to be written into the theme? I’m not a coder but I just thought this would be a cool idea.