openSUSE talk:Build Service Concept GitUpstreamSupport
Since this proposal was written, but before I stumbled across it just now, I made a number of improvements to the tar_scm, set_version, and recompress source services, so they can now handle git repos better. There is still plenty of scope for improvement, and some of the suggestions on this page are still relevant, however some may not make sense, especially those which don't involve source services.