How to build a specific administrable page layout?
Sounds like a job for Panels


  The Panels module allows a site administrator to create customized layouts for multiple uses. At its core it is a drag and drop content manager that lets you visually design a layout and place content within that layout. Integration with other systems allows you to create nodes that use this, landing pages that use this, and even override system pages such as taxonomy and the node page so that you can customize the layout of your site with very fine grained permissions.