Hi,
you can customise Builder in whatever way you want and you are free to design and create any layout you want (on a per-page basis even). If you can be more specific with what you mean, we can perhaps be more specific too. See also: http://ithemes.com/forum/topic/35462-child-themes/#entry166715 and you can watch a video here: http://ithemes.com/purchase/builder-theme/
Ronald

