How to create a layout with different size grid theming with Views?
This you can do using combination of Views and Panels. Views will provide whatever data you want. This will be the easiest and straight.


Views is for -> Fetching the data 
Panels/DS is for -> To arrange Display layout


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.


Or instead of Panels, Display suite also,

Display suit,


  Display Suite allows you to take full control over how your content is
  displayed using a drag and drop interface. Arrange your nodes, views,
  comments, user data etc. the way you want without having to work your
  way through dozens of template files.