AFAIK, Mandriva uses a macro called %mkrel, which instructs their build server to auto create the release number.
Release: %mkrel
If the packager doesn't want this to be automatic, then he can force the number in one of the two ways:
Release: %mkrel 1 or Release: 1
Do you plan to implement something like this?
I have an issue with OpenVZ suse kernels because of the auto release assign. kernel-source packages have different from binary packages release number. This follows in nightmare while building unsupported modules over this kernels because of the wrong symlinks.