Is it possible to record some income for a project that comes from a source other than the customer linked to that project?

Hello David-Xtra, 

Welcome to the Community page, 

So you are able to do this within Quickbooks, as long as you record the income to the project and the product and service is linked via the chart of accounts, so when you set a product and service up or add a despot you use the project name and the category you want or the product and service income account is an income account in the chart of accounts. If your still unsure we would advise you speak to a trained and qualified accountant who would be able to guide you on how to enter it all into your account.  

Thank you for exposing how this can be achieved via products and services in QB Projects.

I was hoping it would be possible to include a second income source without the need to use products to do this.   Maybe this functionality is something that can be added to QB in the future.