People have built complete dashboards mimicking OOB Portal to provide extensive customizations to Business Users, we have come across many of them, creating a toolkit for it may not make sense since Customizations specific to Business Needs are needed or necessitated for such an interface. Also Angular Js and other technologies based headless UIs utilizing REST APIs are built to replace BPM Portal. There are issues of memory leak in utilizing Coaches / services based Portal or Inboxes. Brazos provides a Custom Portal but as I said a lot of customization is needed per use case and a generic approach generally does not solve that.