What I had done before was have a PersonT, CompanyT, ContactT (I refer to the entities as Contacts, not same as your Contacts), then have a unique ContactID within the Person and Company tables. To combine as a Contact List, I used the Company Name or the concatenated person name in the Contact Name field. I just don't want to screw with the template too much and mess it up trying different approaches. Thanks again!!

To manage your projects, you need to create your own project tables.  ABCD is only for storing contacts, not for storing your projects.  For instance, you could create a ProjectsT table that contains ProjectID, ContactorID, SupplierID, StartDate, CompleteDate, etc., anything that pertains to projects.  ContactorID and SupplierID are both "contacts", so you could link them both to ABCD.  That is how a contact database is usually used.

You could change ABCD if you need industry-specific info in your contacts.  I once worked in retail, and my customer table had a few retail-specific fields such as SalesRepID, PaymentTerms, etc., plus all the standard fields like names and addresses.  In your case, you could add a "Role" field to identify each contact's role (contractor, supplier, etc.).  But this wouldn't be a cataclysmic change.  

In fact, I don't foresee anyone needing to make cataclysmic changes to ABCD because (a) ABCD's features, though vanilla, are fairly complete, and (b) most contact databases are fairly similar or even identical.  The Contacts apps in iPhone, Android, Outlook, etc., are hard to tell apart.