Using SharePoint User Profiles for CRM tasks

Is it feasible (and reasonable to do so) to use SharePoint User Profiles like address records in a CRM system?

In a dev project for a  SharePoint Online environment that is to hold 200'000 user profiles and a large number of custom properties, our customer wants to create selections and do reporting and printing against those user profiles. The user profiles should also be mass-edited centrally by a back office, as in an address management tool.

So far we've come up with an architecture that runs all those tasks against an external database which is synced back into SharePoint user profiles via BCS. The information needs to be present inside SharePoint to be used by social and other SharePoint features.

Is there a supported way to run these tasks directly against SharePoint's own user profile service and database?

Thanks for any suggestions.

René