I don't believe there is any way around this without using javascript. The browser renders a page relative to the top-left corner of that page, so anything positioned above or to the left of that 0,0 point is effectively off-screen. All overflow happens to the bottom and the right. It's the same way with content inside of any block element. So if you have an item positioned relative to the right side of the page, wider than 100% width. The part to the left of the 0,0 origin point will simply be offscreen.
I'd love for someone to prove me wrong though.
Here's a javascript solution that works:
<html>
<head>
<style type="text/css" rel="stylesheet">
* {margin:0;padding:0;}
div#box {background-color:green;width:1000px;}
#box {position:absolute;top:0;left:0;}
.clearer {clear:both;}
</style>
</head>
<body>
<div id="box">
asdafdsf
</div>
<div class="clearer"></div>
<script type="text/javascript">
function layout() {
if( typeof( window.innerWidth ) == 'number' )
this.screenWidth = window.innerWidth;
else //patch for IE
this.screenWidth = document.body.clientWidth;
this.el = document.getElementById('box')
if (this.el.offsetWidth > this.screenWidth)
window.scroll(this.el.offsetWidth,0);
else
this.el.style.left = (this.screenWidth - this.el.offsetWidth) + 'px';
}
function eventListener(el,action,func) {
if (el) {
if (el.addEventListener)
el.addEventListener(action, func, false);
else if (el.attachEvent)
el.attachEvent('on' + action, func);
}
}
eventListener(window,'resize',layout);
layout();
</script>
</body>
</html>