I recently bought a theme from Theme forest called Enfold: http://www.kriesi.at/themedemo/?theme=enfold
The pages have an "Advanced layout" building that lets you build you content how you need. I found some plugins like http://wordpress.org/plugins/page-layout-builder/
that are similar, ie, based on modules like accordion, tab, header, icon list etc that you can use to mold your content.
I am really really curious how one would go about creating your own layout builder. IE, is it just an api/interface for shortcodes? I could not find any resources/tutorials so any help in the right direction is appreciated.