Question: Repupose Accounts for Projects? 

BACKGROUND: I have a custom-app deployed and well-fuctioning,  on Salesforce Platform, focussed on project management, no VF or Apex. No sales is done in the app and the Account record functions solely for referencing internal clients who are serviced. We use the Case object as well. The primary object apart from Accounts is Projects and we are heavy users of Activities -- Tasks mostly. We are also ramping up to Library to exploit document management functionality. Approximately 1,500 records in our org currently. I have users who "share" projects and tasks and a need/value is having real-time access to those shared tasks, projects and folders. There are four project record types to address the four categories of projects I've identified among my users.

ISSUE: To accompany Projects, I developed a Master-Detail relationship with a custom object called Folder which is meant to encompass multiple projects, initiatives, etc. The justification for creating the Folder as a Master object was to be able to collect varying projects under one umbrella where all related Activities can be viewed.

I am wondering how appropriate it would be to re-design my app leveraging the Account object to serve either as the Folder object. The Account record is of course extremely robust and provides out-of-the-box team/sharing features.

Mind you, the only function of Accounts currently is to reference an Internal client. It's basically a list of our internal entities and it's not used for billing or anything else. At the same time, couldn't I create a separate Account Record Type to serve as the "Folder" object.

Thinkin' out loud.