If I understand correctly, the "ISO" you are asking for is for building drivers. I don't intend on creating a specific ISO just for that. Everything is available in yum repositories to build drivers (usually you just need make, gcc and kernel-devel), and there's also a docker image at https://github.com/xcp-ng/xcp-ng-build-env
I do prefer Olivier's suggestion, though: going through support, because drivers built for one user through support are made available to other users through our repositories.