There is little one can expect to customize within a Couch backend - it's just tables and forms - so rearrange fields or code an extra button or two in a custom column of list-view table. Backend is for data-entry, user or data simplest management - it is hard to imagine any bespoke edits to the regular workflow. Is it what you wanted to hear?
Customization tools available in Couch are perfect - one can even totally recode list-view and form-view with bespoke html. However, it will be just the same tables and forms in the end. I personally performed a few major edits - added datatable to list-view, tabs to both views and a quick action button to unpublish pages - all to ease my playground experience.
I have seen (and coded some) really interesting dashboards that were completely front-end based off DBFs that presented combinations of data from multiple templates in charts, graphs or compound tables. Those are meant to provide a special ui experience. Such ui/ux is meant to support big webapps - ecommerce admin/customer area or CRM or document management system - see, those are business-oriented scenarios which can not be perfectly fit within CouchCMS's straightforward views.
Do you really have something in mind to tailor Couch for your client that hasn't been covered in this forum?
