We created a proposal to add support for user owned domains to cf-for-k8s. The proposal is available here: https://docs.google.com/document/d/17zIHB-L6tLEJPdbB4JYUEb4ii8w2YIUL5TQU7fV9jlM/edit?usp=sharing
This document should serve as starting point for discussion. We would be very happy for feedback in the document about the use case and the technical implementation.