ctml yes this is one of the extensions I will publish. Refunds are one of the requirements of my project and they will be issued through a user balance. The user balance is also required because we need to allow transferring funds though offline payments like cash and wire transfer.
The core sets of extensions I will publish are: core software (products and orders), categories, pictures, taxonomies, product variations, coupons, user balance, custom units and Stripe payments. Address and shipping will come later as I don't need them for my initial project. Backorders, suppliers and other advanced features are being developed as part of a private codebase and might be available later as paid features.