It would be nice if there was a "shared cookie" tag for binary RPMS that would link a binary RPM to its source RPM. It would be, similar to the COOKIE tag, but it would be common among the source RPM and all the binary RPMs built from it. This would help track RPMs as it currently isn't possible to tell if foo-1.0-1.alpha.rpm and foo-1.0-1.i386.rpm actually came from the same SRPM or if someone just happened to give them the same version number.
What's missing is the glue that points the src.rpm to a set of binary rpm's. This cannot be easily done because a) a src.rpm is implicitly noarch, can be produced on any machines, even if there are %ifarch subpackages. b) src rpm's can be built w/o building packages. c) bianary rpm's can be built w/o src rpm's. cookies have all the above problems.