I wrote a bit back about a gratuitous change in Red Hat's RPM variant breaking backward SRPM readability, in a fashion which stranded users of the earlier Red Hat Enteprise release products (and rebuilds such as CentOS) away from the Raw Hide pool of developmental edge packages.
The fix I outlined: to build and freeze (in time, and against updates) a RawHide domU instance, and to use that domU and an NFS mount back into the earlier dom0 to unpack SRPMs. This works fine for the present.
The full size screen shot is a bit large, but down that link. It takes just a couple of seconds to set up a new unpacking destination, and to do the rebuild, once it is set up.
