I too would like the feature to automatically enter the Project Name.

I own an architectural business in which I have many projects with the same client, and said client will work for different building with different owners, thus I have (1) client but multiple billing contacts, and also have multiple projects located in the same business. 

It is essential that I include the project name on the invoices so that the client and building owner can keep track on their end what project has been paid. 

Attached is an example of how I wish I could create an invoice and the information.