Greetings everyone,
I spent a little bit of time to see if pyrpkg (https://fedorahosted.org/rpkg/) could help with the "building RPMS from a git repo" workflow. Pyrpkg includes methods that can interact with git (cloning, downloading sources etc), koji, and the local mock/rpmbuild build processes among other things. You may know pyrpkg better as the backend for fedpkg in Fedora.
I have a very bare-bones configuration at https://bitbucket.org/bstinsonmhk/centpkg that I thought I would share. Is the community interested in such a tool? If so I'm happy to keep working on it, perhaps with the help of others who are interested?
Cheers! Brian