This will allow you to invite clients to a project where they can view a very simple client portal which shows associated Email, Forms (submitted/unsubmitted), Files, Calendar.
As a Hive App the Client portal could be configured at the workflow template level so forms etc are automatically applied to projects for external clients.
17Hats, Dubsado, SuiteDash - all do the job but combined with Hive this would be a gamechanger and a one stop shop. I have tested all of the platforms available and they all fall short on the project management side, so this would be a game changer.
We have a wedding stationery business so client portals are extremely helpful to keep everything organised and very simple on the customer facing side.
If it's not possible then an integration with https://www.joinportal.com would be great (albeit expensive for what they offer)
I have attached 2 examples of the customer facing side