I've always had to use JavaScript to simply loop through all the elements and add their widths together then set it to the parent element. Here's a basic example:
http://jsfiddle.net/ZfSHJ/
You definitely want to use margins in this case. Top is tricky because it acts weird with the height. To get your desired affect, you'd have to add a different "top" to each of the outer divs. ...
I'm totally new to Drupal. I'm hoping there's a drupal module out there to help me, but I haven't been successful in setting it up. Basically, I just want to display a listing of all the...