There is an easy way to use different form layouts, and it's the same whether you use the form builder or ad_form, because it's done in the .adp file.
You define which form layout you want to use with the "style" attribute of the <formtemplate> tag. For example:
<formtemplate id="my_form" style="plain">
The templates which implement the different styles are stored in:
packages/acs-templating/resources/forms
