If you want to use a non standard layout for a live tile. One option would be to create the tile design as an image on the server then push it to the phone via a push notification. I had to use this option for an app that I created a couple of years back.
Microsoft discusses how to use the XamlRenderingBackgroundTask to draw custom live tiles in this Build Session. That is for Windows Phone 8.1.
If you want to draw custom live tiles in previous versions, you have to draw and download it from a server, unfortunately.