Yes, we have created a Brizy scratch theme dedicated to the author program that will help you kick start your development process.
This theme was optimised for speed. It is basic theme, stripped down of all unnecessary code and doesn't come with any plugin that might impact performance in any way.
Moreover it comes with a demo import feature that you can use to let your clients import the demo content at a press of a button.
You can download it, install Brizy PRO and start building your commercial WordPress theme on it. Let us know if you have any questions by emailing us on firstname.lastname@example.org.