I finally found this related post http://support.advancedcustomfields.com/forums/topic/need-a-better-way-to-organize-fields/, which talks about this same need for organization. I actually am using the repeater field now (with widths set on its items) in order to group my fields. It’s a hack, but it’s the best I can do. In that link they get into deep conversation about setting up the admin with grids, but just being able to group my content in sections (and set the width of the items) or nest the tabs would be enough for me in almost any situation.
