[CentOS-devel] Is there a "mock" setup or downloadable list of tweaked packages for testing CentOS 6 builds?

I may be able to pry time free to test CentOS 6 builds. But I don't want to burn useful worktime with building mock files and manually rebuilding all the SRPM's. I've got access to licensed RHEL 6 to use as a build environment, and to do what gcc does: build a "staging" setup, then do a clean rebuild with that staging, then do a final rebuild to make sure material matches and look for discrepancies.

Is this already done somewhere I can get a copy, so that I don't have to burn time re-inventing the wheel? I'd particularly like to make sure that a current "mock" is in the "extras" repository, to speed build times. (The current mock in epel-testing is much faster and more efficient than the older mock releases.)